Running one game is a lot of work. Running multiple games is even more work. It is also a situation I find myself in quite often, and quite often by choice. I'll admit to being a bit of an addict, but at the same time when there are things you want to see happen in games sometimes you have to run them yourself. Today though, I want to talk about a few things that helps when you find yourself GMing for more than one game.
First, A Schedule Helps A Lot
The first thing is having a schedule. I hear about games that have ad hoc schedules, and I can't fathom how they work. One of the biggest problems you see people talk about with having game is getting people all free at the same time, and having no set day to me just makes that harder. I find it so much easier to figure out who is available on a set day, and is willing to lock in that time and go from there.
When running multiple games, having a set schedule is a must. You just can't be juggling schedules for two games. Having a set time for them both to happen lets you schedule everything out from the game time, to prep, to everything else. It also lets you have enough time between games to do your prep for one after the other is done. Trust me, having games on consecutive days makes prep really hard, especially when both games are coming up on big moments that really deserve full attention.
Second, Plan In Arcs or Plan Ahead When Possible
One thing that has really helped me out is doing my best to make small stories and arcs that take up several sessions, or are designed to run over several sessions. I don't need to have the whole thing done, just the framework for it. This framework gives me something to run with in the event I don't have a lot of time to prepare for one game or the other. It also makes planning for an individual session easier because I know the overall flow for where things are going which means prep for a specific session is about the specifics about that chunk, and room for improving should the PCs go off the rail. And improv is a big part of all GMing, but improving when you know the general framework of what needs to happen? So much easier than trying to make up the moment to moment stuff AND the overarcing stuff at the same time.
Third, Leave Yourself Outs
This in general is just good GMing, but always leave yourself outs. Sometimes it is good to not have everything locked in and carved in stone for how things are going to go. A vague outline of how things should go, an idea of how the PCs might interact with things will get you a lot further at the table. It means you're not married to anything, which in turn means the PCs can change things more. This is solid GMing because it gives your PCs more chance for agency, and that will make them more invested.
Fourth, Take Notes and Review Them
Finally, note taking is super important for multiple games. This may seem obvious, but I went for years just 'keeping the game in my head' and it worked fine. Of late though, taking notes has been great especially when running multiple games. Having a written record at the time reminds not only of big things, but of small things. Those small things, those tiny details you may forget, can be so important for stringing things together and making people feel like you're a god damned legendary story teller. Read those notes when doing prep for the next session. Revise your plans with the notes of what has happened in hand. Shift things as need be, and find ways to make those small things PCs did matter in the bigger picture to the game.