One of the first tips you’ll receive when asking for advice on being a Dungeon Master (or Game Master for other TtRPGs) is to improv. However, what does it mean to improvise? Well, in my experience, there are three different ways to improvise when it comes to DMing. I’ll start with the simplest way that you have to do, no matter what, and go into more complex ways as we continue.
Responding to Players
It doesn’t matter how much you prepare a session, or if the adventure is a pre-written module made by professionals. Your players will ask/do something that you can’t possibly prepare for.
Trying to find the culprit of a crime? Your druid might Speak with Plants and ask the bushes who they saw. No where will you find information on what that bush saw, or what it will say.
If you find a market, your players might ask what magical wares the vendor has, and you’ll have to make up a list of items, without handing the players the Dungeon Masters Guide with the full list of magical items.
If your party decides they want to “Persuasion” the villain, instead of fight them, what terms and conditions will this villain accept for a truce?
These are the things that you will have to face on your first attempt at running the game, and these are the things that will give you the most stress. It’s okay to be stressed, as you continue to play the game, you will find things that, over time, will be your go to responses for certain questions/actions.
Druid speaks to plants? I give them a funny voice and a bizarre sense of time.
Magical vendor? Each player rolls on the A-I charts (depending on level) of things they find as they walk around. This way they don’t have to think of all the magical items they might want, but they also don’t get the whole book to choose from.
Persuade the villain? If they made a deal, then they are beholden to that villain in some way (requiring a Warlock multiclass perhaps?).
There are little tricks you’ll begin to pick up, but the main goal, is to not be so stuck to your plan/story, that you aren’t prepared for unique actions that require you to change your initial plans.
No matter what you prepare, your players will surprise you.
When you are a better, more experienced DM, you might be interested in running a Sandbox game. Sandbox games are similar to a regular adventure you are familiar with. Normally, you have a location, a primary conflict, and details needed to fill out those two aspects. However, with a sandbox game, you really only have the location.
When building out a location (such as a city) part of that is having several smaller conflicts or rumors, that make the city feel real. There’s never only one problem going on in town, but usually there’s only one you really want the players to care about. Now, instead you’ll have several “smaller” conflicts for the players to find out about, and it’s up to them which one they are interested in.
If you party comes to the town of Port Lionen, there might be rumor of pirates, a haunted house, and a Merfolk/Sanguin fight. Instead of pushing them to one, you leave it up to their interests, and see where they want to adventure.
This might seem like more work, but it actually balances out the level of preparation. Instead of planning an entire adventure before you start, and make adjustments along the way, you only ever prepare for one session worth of information, and see where the game takes you. Once you get try playing a game Sandbox Style, you’ll feel more comfortable with adjusting to your players in a prewritten adventure.
Lastly, we have playing in the void. This is a fully improvised session. You have nothing prepared, all you know is who your players are, and that you’re playing. After that, everything is made up.
This is something I’m practicing with my quarantine time. I set a time with my players on Discord, and a list of 50 adventure hooks, each one or two sentences. Then, as we log on, I ask them to pick a number between 1-50, and as they open up their character sheets on DnDBeyond, I read the hook. I usually let them chit chat for about three to five minutes as I quickly come up with ideas. I have multiple tabs open on my computer, such as donjon, Roll20’s compendium, and all the books’ pdfs, so that I have lots of information and ideas at my fingertips.
Playing in the void is probably the most nerve wracking DMing I’ve done, as I have no idea if my ideas make any sense, as I’m not able to think about them whatsoever. I have to say what comes to mind, almost immediately, and hope that my players accept it. I’ve learned two things the most as I’ve practiced playing in the void. First, really listen to your players. They will tell you what they want as they discuss with each other. If someone starts talking about a secret subplot, try to see if you can work in a secret subplot. Secondly, even as you try to guess where they are going, they will do something else, reinforcing the idea that your players will surprise you, regardless of what you plan.
No matter what path you take, improv is a vital aspect of DMing, and one that you will get better at the more you play, but you have to play to get better.