The main lesson I learned from this game is to be patient when you're winning. It's foolish to start rushing moves hoping for a quick win before your opponent logs off. Ironically, in a blitz game I would have been more likely to just play 21.g4 right away. Here I took just enough time to second-guess myself but not enough time to see that the move really was winning. It's certainly not the first time I've done that.