The main thing I’ve learnt is to tell your players as much as you can before you start playing. Give them background lore, locations and maps, give them descriptions of well known characters - tell them everything a normal person in the setting would know and they’ll engage with the story far more, because they feel like part of the setting rather than an outsider looking in.
For my most recent campaign I wrote a 9 page guide that detailed mechanical restrictions, backstory requirements, and common themes that would crop up throughout the campaign, and everyone turned up to their session 0 with a complete character whose presence and motivations closely fitted the story, including the guy who was in prison for the first 4 sessions.

My players were unusually competent and focused. I had never experienced this as a player before, so I needed to do a lot more writing.

How incapable adults can be in figuring out their schedule ahead of time. And committing to it.

what suprised the most:

• how much time things take at the table
• what players don’t get that seemed super obvious to me when i prepped a murder scene for example
• how much time i put into things, that don’t matter for the session.

what advice i would have liked to have:

• if something hinges on the players finding a specific thing, the thing exists atleast 3 times.
• don’t prep a plot, prep situations and know the motovations of your npcs, the story happens at the table and trying to prep that beforehand only restricts you.
• get your things in order before the session, if you know you need specific statblocks write them down in a way you can reference them quickly, if you need a dungeon with a complex layout, draw yourself a map before hand, have a roomkey where you can quikly findt it and so on.
• present players with possible hooks for the next session, that way you can prep 2 or 3 specific things instead of “everything”, and the path they did not follow might still be something you can use later.

That the campaign probably won’t finish. And then provide ways onhow to wrap things up somewhat satisfyingly in 2-5 sessions. Because you know that’s how much time the group has left. And the group knows it too. So how to wrap it up

I learned that my players will break any kind of logic puzzle in ten second flat, but can’t decipher a simple investigative clue to save their own life.

I was baffled at how much guidance I have to give them towards unraveling the mystery. I don’t know if I’m not that good at engaging their interests, if my clues are too obscure, of if they are simply not that perspective. They sure are creative with how they tackle problems tho, their shenanigans are hilarious

It wasn’t my first campaign, but it was a game I ran for a group that hasn’t played before, and it was funny how unintuitive a lot of “player actions” can be if you’re not used to it. Like, they didn’t know what they could do?

I had an NPC slip something under the door, and when the players opened the door they could just barely see the NPC nip around a corner at the end of the hall. This was “meant” to be a chase. Instead they were basically like “huh… I wonder who that was. Guess we’ll never know” 😛

Or when one of them talked to a witness of a crime and I described the witness as “eyeing you suspiciously and only barely nodding in response to your greeting” they were like “I don’t think he likes me, I don’t want to disturb him, I’ll leave him alone” 😅

It was all fully my fault, of course, but I was used to playing with much more active and plugged-in players, and fully dropped the ball with players that were a lot more passive, either from lack of experience or just mismatch between players and game genre.

So for them, I think a few railroads would have actually helped them quite a bit. Or if not railroads, at least maybe some bumpers or training wheels until they start to figure out what it means to have agency in a genre story.

You know, what really surprised me was how natural it came. I’m not saying I didn’t make mistakes, or that everything worked the way I thought it would. It’s that whether I had a plan for a session, was winging it, or was crafting long term setups that didn’t pay off for months, it flowed for me.

Reading my players, adjusting to the vibe of the table, switching things on the fly, it wasn’t a struggle.

Mind you, that’s my first campaign. There was a little bit of struggle learning d&d as a whole, and that learning curve meant the previous adventures were clunky as fuck all because I was just wrong about a bunch of stuff. Thac0 alone was a huge factor. But once I grasped the rule set, making my own campaign and running it felt as natural as breathing.

I would recommend that for the first session have 1 obvious hook. This lets the players obviously follow the initial path and explore your world. After that either have 1 hook or many hooks at the same time. When you have many hooks ask what they are considering so you can expand on the things they are interested in. The other hooks can either linger or resolve them self behind the scenes. Players love agency even if it’s something stupid like what pub to go to.

Last thing I ran was Phandelver and that shit is on tracks. Players said they had fun.

That the next session could be the last, I like that some resources for games have guidance on that. For example the Mothership Warden’s Operation Manual has a section on what is the omega to the alpha of session 0.5.

Going off of that perspective, I try hard not to prep more than the session after next as well as use my cool thoughts/NPCs/threats/etc. sooner rather than later.