The Ultimate Guide to Not Screwing Up Your D&D Prep Time

So here’s the thing. The more I run tabletop RPGs, the easier it gets to spot when a new Game Master is making rookie mistakes.

And honestly? The biggest screw-up I see is prep time. Either they’re scrambling together something five minutes before the session, or they’re spending forty hours painting miniatures that will appear in one scene.

Neither approach works.

Let me tell you why under-preparing is such a disaster. It’s like dominoes falling. When you don’t prep enough, everyone at the table knows it.

The game stutters along awkwardly, your players feel like their choices don’t matter, and you’re basically sweating through your shirt the whole time. Not fun.

The fix sounds simple: just prep more! But how much is enough? Well, that depends on a bunch of stuff.

How experienced are you with the game system? Are you making everything from scratch? How many players do you have? How long do your sessions run? What game are you even playing?

Let’s figure out how to actually manage your time without losing your mind.

Step One: Pick Your Poison (The RPG System)

Before you do anything else, you need to choose what game you’re running. This matters way more than you think.

Take Dungeons and Dragons, for example. The Dungeon Master creates pretty much everything: the world, the story, the encounters, all of it. Compare that to something like Apocalypse World, where everyone at the table is building the story together.

Most games fall somewhere between these two extremes, but they’re great examples of the spectrum we’re dealing with.

Now, a quick disclaimer. These time estimates assume you’re not going completely overboard. If you’re hand-painting miniatures or building elaborate dioramas or whatever, that’s awesome, but that’s extra credit.

I’m talking about the basics: creating NPCs, designing encounters, drawing maps, writing story beats, and building your world. If you’re spending way more time than I suggest and getting great results, keep doing your thing! But if you’re burning hours and not seeing improvement, maybe it’s time to rethink your approach.

Dungeons and Dragons: Welcome to Hard Mode

In D&D, the storytelling is kind of collaborative, but let’s be real: you’re doing most of the heavy lifting.

You control every monster, you make the maps, you flesh out every shopkeeper and villain, you build the entire world, and you create encounters that drop sweet loot. It sounds exhausting because it kind of is.

But it’s also incredibly rewarding.

D&D also has a million mechanics that both you and your players need to understand. This cranks up your prep time because you need to think through spell interactions and special abilities before you throw that dragon at your party.

If you’re creating a homebrew world with a unique story, buckle up. Everything comes from your brain. Every. Single. Thing. But when your players explore this world you’ve created just for them? That feeling is unbeatable. Just know that the upfront time investment is massive.

There’s another option, though: published adventures. These come with pre-built worlds, pre-drawn maps, and ready-made encounters. They’re lifesavers for busy DMs. The catch? You need to do your homework.

Before your first session (maybe even before Session 0), you should read the entire adventure front to back. Take notes about important characters and plot points. That wa,y when something comes up mid-session, you’ll understand how it fits into the bigger picture.

Collaborative Storytelling: The Easy Mode Nobody Talks About

Games like Apocalypse World that use the Powered by the Apocalypse system flip the script entirely. Your players have a huge say in what the game looks like.

Before anyone even makes a character, you all sit down and talk. What’s the setting? Who are the important NPCs? Why are we here? What caused the apocalypse in the first place?

As the GM, you’ll have a general idea of who the villain is and what they want. You’ll want to prep a bunch of NPCs beforehand. Beyond that? You’re pretty much good to go.

The minimal prep time is honestly the best part of these games. There’s way less work between sessions because you’re building the story together in real time.

Before Session 0: The Foundation

Session 0 is where everyone gets together to create a game you’ll all actually enjoy. If you’re not familiar with what a Session 0 is, definitely look that up because it’s crucial.

Before you do literally anything else, read the rulebook for your chosen game. Learn the mechanics, figure out how to run a game, and absorb everything about how to play.

Read blogs and watch actual play videos.

This is where most of your initial prep time goes, no matter what system you pick. Block off as much time as you need to get comfortable with the rules before moving forward.

If You’re Running a Homebrew D&D Campaign

Do all the big picture stuff. Create your world map. Write bullet points about the major cities and towns. Build a timeline of the realm’s history. Decide what the overarching plot will be. This takes forever, but here’s the secret: it actually saves you time in the long run.

I usually give myself a couple of months before Session 0 for a new homebrew game, then another month before Session 1. I’ll announce the game, ask my players what kind of theme or setting they want, and then get to work. I keep asking for their input right up until Session 0.

Session 0 Prep Time: However long you need. Don’t rush this.

If You’re Running a Published Adventure

Hope you like reading, because you’ve got a book to get through. The good news is that all the balance testing and creation work is done for you. You just need to read everything and tweak the parts you want to change.

Published adventures are perfect for new GMs or anyone who doesn’t have tons of free time.

Session 0 Prep Time: Long enough to read the whole thing cover to cover.

If You’re Running a Collaborative Game

Spend about an hour before your first session creating NPCs, villains, and evil organisations. Don’t go too deep, though.

Make rough outlines so you can introduce these characters and then develop their personalities while you’re actually playing with your group. Everything else, like the setting, gets built during Session 0.

Many of these games have character creation as part of Session 0, so make sure you know that part of the rules inside and out. Your players will have tons of questions about mechanics.

Session 0 Prep Time: 30 minutes to an hour, tops.

Before Session 1: Set the Tone

Your first real session is huge. It establishes the vibe for everything that follows and introduces the characters to your world. No pressure, right? But if you nail this first session, every session after becomes easier to prep.

Homebrew Campaign

Schedule at least a week between Session 0 and Session 1, maybe up to a month if you need it. Now that you know your setting, create a few dungeons and plot hooks. Add tons of detail to the starting area where your players begin their journey. This is all about depth.

Think of this as an investment. The more time you spend prepping before playing, the less time you’ll need between later sessions. Here’s a good rule: prep for at least as long as your first session will last. If you’re playing for 8 hours, prep for 8 hours. Manage your time accordingly.

Session 1 Prep Time: At least as long as the first session itself.

Published Adventure

Your prep is basically re-reading the first chunk of the book. Read up to where you think your players might stop, then read a few pages beyond that. You probably won’t get that far, but better over-prepared than caught off guard. Get familiar with it and take notes. Add extra details or modify things as needed.

If you use battle maps, maybe draw a few ahead of time, depending on how fancy you want to get. If something can be sketched quickly during the session, just do it then. Your time is valuable, and this gives you more time to read and plan the actual game.

Session 1 Prep Time: 30 minutes to an hour minimum.

Collaborative Games

Make a couple of maps and figure out how you’re going to kick things off. For these games, your first session needs the most prep.

Right now, your world is like a blank canvas. You need to know where to start. Use what you and your players created during Session 0 and brainstorm potential problems and conflicts. Make more NPCs. Add more details to the world.

Session 1 Prep Time: 1 to 2 hours.

Every Session After: The Rhythm

From here on, you’re playing regularly. That might mean once a week, once a month, or somewhere in between. The more time between sessions, the more prep time you have available.

But here’s the key: your prep time should match how long your sessions are, not how much time you have between them.

Homebrew Campaign

I forget where I first heard this advice, but it’s golden. Spend at least half as much time prepping as your session will last. Playing for 3 hours? Prep for at least 90 minutes. I also cap it at the session length.

Don’t prep longer than you’ll actually play. This keeps you focused and prevents burnout.

This is where all that early worldbuilding pays off. You’ve already created your world, cities, plot, and major NPCs.

You don’t need to rebuild all that every week. You’ll have a clear focus on what needs planning. If you rushed through Session 0 and the pre-Session 1 work, you’ll be scrambling between every session.

By the way, I don’t count creating homebrew mechanics, races, or classes in this time limit. When I make those, I’m planning to reuse them across multiple campaigns. Session prep is just for that specific session.

Session Prep Time: Between half and equal to your actual playing time.

Published Adventure

Your strategy stays pretty much the same as in Session 1. Keep reading ahead and taking notes. Create whatever you need to run the session smoothly. Honestly, I love sneaking these into homebrew campaigns or running one-shots occasionally just to give myself a break.

Running a published adventure isn’t necessarily easier than homebrew, but it definitely saves prep time. They’re game-changers for people who want to GM but have busy lives.

Session Prep Time: 30 minutes to 2 hours, depending on session length.

Collaborative Games

Keep generating ideas for the campaign and more NPCs. Focus on bullet points about these ideas and characters. They should grow and change through interactions with your players.

During sessions, take detailed notes about what happens. Review these before your next game and think about how to use the last session to move things forward.

Hot take: Taking great notes during the session is more important than prep time for these games. If you over-prep, the game stops being collaborative, or you’ll waste a ton of time on stuff that never gets used.

Session Prep Time: 30 minutes to an hour.

The Bottom Line

The longer you GM, the better you’ll get at prepping. You’ll discover shortcuts, your improv skills will improve, and you’ll know the mechanics cold. All of this shaves time off your prep and gives you more energy to develop your story and create interesting characters.

I think most players would rather play half as often with a well-prepared GM than play every week with someone who’s clearly winging it. If you’re busy and can’t carve out enough prep time, just add more time between your sessions.

And listen, as a player, I don’t want my GM stressing out trying to get everything done. It’s completely reasonable to cancel a session because you didn’t have time to prepare. Life happens.

Everyone understands that. I once had to take a month-long break from my game because I was studying for a huge certification exam. My players were totally cool with it and actually encouraged me to focus on the exam.

Take care of yourself, prep appropriately, and your games will be amazing.

Frequently Asked Questions

What if I’m running out of time before a session and haven’t finished prepping?

First, take a breath. You’ve got options here. If you’re really not ready, it’s totally fine to postpone the session. Your players will understand. But if postponing isn’t an option, focus on the essentials.

Know your opening scene, have a rough idea of 2-3 encounters or scenes, and prepare to improvise the rest. It won’t be your best session, but sometimes good enough is actually good enough.

Also, don’t be afraid to tell your players you’re running a bit light on prep. Most groups are happy to have a more roleplay-heavy, combat-light session when needed.

How do I know if I’m over-prepping or under-prepping?

Great question! You’re under-prepping if you’re constantly scrambling during sessions, you can’t answer basic questions about your world, or your players’ choices feel like they don’t matter because you haven’t thought through consequences.

You’re over-prepping if you’re spending hours on content that never gets used, you feel frustrated when players skip your prepared material, or you’re getting burned out between sessions.

The sweet spot is when you feel confident going into a session, you can roll with player choices, and you’re not exhausted from prep work.

Will prep time get faster as I gain experience?

Absolutely! This is one of the best parts about sticking with GMing. As you run more games, you’ll get faster at creating NPCs on the fly, you’ll build a mental library of encounter ideas you can adapt quickly, and you’ll know the rules well enough that you don’t need to look everything up.

Many experienced GMs can run great sessions with half the prep time a beginner needs. You’ll also get better at identifying what’s actually important to prep versus what you can safely improvise.

Just don’t expect this overnight. It usually takes running a full campaign or two before you really hit your stride.

What do I do when my players completely ignore everything I prepped?

Welcome to GMing! This will happen constantly, and it’s actually a good sign that your players are engaged and making real choices. First rule: never try to railroad them back to your prepared content.

That feels awful for everyone. Instead, learn to recycle your prep. That dungeon they skipped? Move it somewhere else. That NPC they never met? Change their name and location.

The combat encounter they avoided? Save it for later. Also, this is why prepping situations and NPCs is better than prepping a linear story. If you prep “the bandits want to steal the artifact” instead of “the players will fight bandits at the bridge,” you can adapt when your players take a completely different route.