I've been struggling with my D&D game. The players all assure me they're having fun, and they seem to enjoy the game so I'm not worried about that end. However, even with them having fun, I know that it's harder for me to prep a session for D&D than it is for other games I run. At first I had it chalked up to system familiarity. I was still learning D&D, and I had years of experience with other systems. Then I noticed that even with systems I didn't have that familiarity with I didn't have the same problems. It wasn't until my L5R game was close to coming off hiatus and I started prepping for that that I realized the problem: for whatever reason, I have been prepping for D&D differently than I have for other games.
Encounter Based Preparation
I've been mentally referring to how I prepare for D&D as "Encounter Based Preparation." D&D as a system is very much built around encounters. There are suggestions on how many encounters PCs should face per short or long rest (i.e. how many per day) and recommended amounts of time that PCs should be spending at different levels. The game, while it has some vague suggestions for RP based XP really only gives it out specific numbers for combat encounters. Basically, Rules As Written, you get XP for fighting with bonuses for RP or story, not the other way around.
Because of this, and not wanting to do D&D wrong, I've been preparing for encounters before preparing for narrative. I figure out what encounters I want the PCs to have built around the Challenge Ratings of the monsters, then look to where the PCs are in the game and what's going on to choose exactly what monsters they're going to fight. And then I weave the narrative for what's going on around that.
Narrative Based Preparation
For other games, I do the opposite. I look at where my characters are and what's going on, and figure out what is happening from there. I figure out the aspects of the characters I'm going to challenge and poke at, and once I have that in mind I build encounters - combat or otherwise - around it.
For example, in my L5R game I had two players playing twins with a big sibling rivalry going on. As such, for several sessions the plan was built around how would I bring the sibling rivalry to the fore - without driving a wedge between the characters - and let them compete and act it out. If that involved a fight, it involved a fight, but if it involved their mother giving them both a courtier and telling them whomever did better in court over the winter would win becoming their father's heir.
My Personal Preference
There is nothing wrong with either approach, but I very much have a lot more experience with the latter than the former. I am, by my very nature, a story teller type GM, and I think the majority of my players - if not all of them - are story teller type players. Sure, we all have that mechanical crunch desire to 'win' but we'd rather a great story than 'defeating' the campaign if you know what I mean.
Which means that going forward I'm going to have to try and adjust how I prepare for D&D. Which means I'll need to keep a close eye on my players' feeling of progression and their XP growth. Not the end of the world. The milestone system has been out as an official option or unofficial suggestion for as long as D&D more or less.
Still, I felt this was worth sharing. But what about you? How do you prepare for your games?