So you wanna DM, hm? Excellent! DMs are awesome and in short supply. I get a lot of people asking for tips, so here are the things I wish I knew when I was getting started. This is the deep dive; for fast tips see the fast tips page.
1. DMing is much easier than you think it is. It’s easier than playing. Think about it: every player has at least two and sometimes more options in battle. (Attack or buff a party member? Which weapon? Do I need healing?) You have one: who is my low-level bad guy gonna smack? You don’t have to worry about healing, temp HP, leveling up, nothing. You don’t have to worry about spells if you don’t wanna. I didn’t run a magic-using bad guy for 5 years and nobody noticed.
“Don’t I have to memorize all the rules?” No. It’s a good idea to have a vague idea of them, but don’t panic if someone asks if a buff stacks, or exactly how long a condition lasts, or if something does or doesn’t count in this particular instance. I’ve found the easiest way to keep the game moving and to keep everyone having fun is to say “I don’t actually know, so I’ll allow it for now, and look it up later.” I say this even if it looks crazily overpowered- most of the time, the player was right! (You are going to want to actually look it up as soon as you can, preferably while the players are still there.) This is a very complicated game! Nobody expects you to have everything memorized.
2. The first impression I had when I ran a game for the first time ever was “holy cow, they’re going along with this!” Your players are on your side: they want you to succeed. Relax!
3. It’s easier to overprepare than you think! My first game had entire archipelagos, fleshed out with named islands and rivers and cities and dominant races and religions, that we never even mentioned in the campaign. But I’ve come to understand that not everyone will read the packet I hand them, no matter how well all the names match each other because yes, I put that level of thought into it. I still sometimes go overboard (I might have an entire Draconic conlang, complete with grammar rules) but I understand I’m doing it for me, and I no longer get mad if someone declines my short novel of worldbuilding notes.
4. It’s soooo tempting to ask each potential player when they’re free and select a good mutual time when scheduling the game. I still make this mistake, knowing full well it’s not gonna work. Half the players will swear they’re free “all the time” but remember a commitment every specific time you mention. The other half will promptly declare they only have free time one night a week… and it’ll be three different nights. It’s honestly easier to say “I can do this on Thursday night or Wednesday night, 6-9 either time. Which is better for everyone here?” (Last time I did this we wound up meeting on Tuesday 6:30-9, but I’m still calling it a success.)
5. I’ve seen a lot of people suggest one-shots for your first time. Honestly… one-shots are a little harder than people make them out to be, since you have to watch the time. Nearly every time I play one I hear “oh my gosh, this was supposed to just be a couple of hours…”
Pick or plan a one-shot, but understand that it may take two or three sessions.
6. I think the essentials kit comes with “pre-gens” or pre-generated characters, all ready to go. If your players want to use them, that’s fine. If you want your players to use them, that’s also fine. If they’re dying to roll their own, here are some essential things to say:
A) “It’s my first-ever time DMing, so I’m not up for evil characters. No evil PCs in this campaign.” I still use that second sentence after 10 years of DMing. Evil PCs are the sort of thing that, in the hands of the wrong player, will cause a lot of hurt feelings. And honestly, if someone’s first question is “can I be evil?” …they’re probably that exact wrong player. I’ve made a lot of people pretty bummed when they hear they can’t be evil. I’ve also had very little table drama. I regret nothing.
B) “It’s my first-ever time DMing, so we’re using the PHB only. Please save the fancy builds for after I get my feet under me a little better.” That may sound limited, but it’s still 11 classes, 9 races, 13 backgrounds, and… I don’t know, 30-something subclasses? That’s plenty. Bonus if your players are also newbies: this is more than enough to make a newbie’s eyes cross.
C) If anyone gives you any lip, your line is “Oh! I’m sorry… I’ll be happy to take on the next game if you’re wanting to DM.” Usually that shuts the lip, but if they protest, “well, if you’re not going to DM, then I will, and I’m saying no evil PCs in my game.”
D) Again, if you don’t want to mess with character creation, “It’s my first time DMing and we’re all using pre-gens” is a perfectly acceptable thing to say!
7. I’ve heard many people advise newbies to keep the party small. I’ve noticed that established campaigns swell like my personal worldbuilding notes, so this is generally sound advice. That having been said, running for 3 people isn’t that much different from running for 6 people.
There is one player you should allow, and I don’t care how big your party is: a veteran player offering to help newbies. When you’re behind the screen, having an actual player helping is INVALUABLE. New players have a lot of questions, and having a veteran is AMAZING. They, not you, can point to someone’s AC, hand them a d6, notice that they just rolled a d12 instead of a d20, remind them to mark a spell slot, or remind them how mods work… for the third time… this sesh.
8. If you have a player trust you with a problem, resolve it before the next sesh. This pertains to interpersonal problems as well as simple rules questions.
Books can be written about interpersonal problems. Even in a deep dive, I can’t really address even most possible problems and how to deal with them. Do let me say this: at some point you’ll have to decide which is more important; avoiding conflict or having a happy, healthy table. I can’t make the decision for you. But I’ve noticed personally that the latter is the right decision for me. It’s awkward. Sometimes it really hurts. But if you ignore bad behavior, you’re going to have all your good players leave. Rip off the band-aid. And do it quickly. Problems like this don’t get better if you hope hard enough. They just get worse. Talk to the person. Yesterday might have been ideal, but today is better than tomorrow.
Last bit is the bit you already suspected: if you love D&D, learn to DM. it’s always easier to find players than it is to find a DM you like.