When I was taking my teacher classes, we were encouraged to be “Reflective Teachers,” even to keep a teaching journal or diary.  While few teachers have the time to write a diary, most good teachers do try to evaluate their lessons and make improvements.  We may formalize those suggestions in post-observation reports or discussions with administrators, or we may just keep sprucing up our lessons and labs each year on our own.
In the same manner, good GM’s are reflective as well.  While most of us do not have time to write post-session journals, we should make a little effort to mentally assess how our games went.  Below is a list of questions to help with that process. The suggestions are listed for several gaming situations, though many of them cross-over.
FOR A CONVENTION OR ONE-SHOT GAME
  • Did I introduce myself and give the players a chance to introduce themselves, even if it is only their name and what they usually play?
  • Did I briefly explain any dice rolling conventions or special rules for the game?
  • Did I make sure everyone had dice or other needed materials?
  • Did I make an effort to involve folks who were not participating?  (An easy way to do this is when the party is talking to an NPC.  You can ask “Do you have anything you’d like to ask them before we move on?”  Or better yet, have the NPC ask.)
  • Did I make an effort to be fair to all the players as much as is reasonable?  (And for a one-shot, even to lean things in the players favor?  After all, they signed up for your session over others).
  • Did I thank them afterwards?
FOR THE START OF A NEW CAMPAIGN
  • Is the campaign theme clear in my head, and did I make things clear to the players before they signed on?  (For example, a DM shouldn’t spring “adult” themes on unsuspecting players.  I’ve heard of this happening and folks walking away from the campaign.)
  • Did I help with character creation or character choice so that everyone has a role to play?  Did I try to accommodate unusual requests, while still avoiding overpowered or unworkable characters?
  • Did I tell players whether this is a limited duration campaign, or an open-ended, ongoing campaign?
  • Did I make sure players understand any house rules, prohibited classes, or rules changes that will be used during this campaign?
DURING AN ONGOING CAMPAIGN
  • Did I give a clear recap of previous sessions at the beginning of each session?
  • Did I ask players to help with the recap or remind me of anything I missed?
  • Did I make fair accommodations for players who can’t make it?  (Usually better than killing their character while they are away).
  • Did I make sure to give each player their turn in the spotlight?
  • Did I handle rules questions (or even challenges) calmly and fairly?
  • Did I make sure that the players were talking at least as much as I did, and preferably more?
  • Did I summarize the session at the end to give them some sense of accomplishment?
FOR ANY CAMPAIGN
  • Are they having fun?
  • Are you having fun?
  • Are your players coming back?
This list isn’t meant to be exhaustive.  Nor I am trying to suggest that we will all hit all of these notes every time  (I’m sure I don’t). It’s only meant to be a start, and please feel free to add your own thoughts in the comments section.