Many professions build in after action reviews to their daily work. This is an opportunity for everyone on the team to think about the activity they’ve just experienced and express what’s on their minds. The military does this well by focusing explicitly on fixing deficiencies and maintaining strengths.
In my experience, groups are most likely to debrief after something has gone wrong. In Dungeons and Dragons, my own group spends more time discussing the tough encounters than the easy ones. My wife’s World of Warcraft raid group always spends time discussing their tactics after they’ve wiped a few times. This is not a bad instinct. After all, if you’re characters are nearly dying (in my example) or repeatedly dying (in her example), you know you need to work on something.
We often miss the opportunity to improve even after things have gone well. If you don’t explicitly identify the good stuff, you aren’t as likely to sustain those strengths.
When you’re debriefing your games, it’s best to begin from a position of ‘what can we do better?’ This feels a lot better than starting with ‘what did we suck at?’ By holding to a spirit of improvement, you’re free to compare what went well with ways it could be improved, and you can also discuss mistakes and ways to avoid them in the future.
Even if you can’t find time to debrief with your group, it pays to do it electronically via email, group forums, twitter or whatever.