As I tell all my chess kids, chess games are almost always lost, not won. Of course the winner has to see how the game was lost by the other player, but the point is that "The winner of the game is the player who makes the next-to-last mistake. - Tartakover". The key to improving your game is to become more tactically aware, and this is hardly ground-breaking advice. But even so, I've been playing a lot of speed games online lately (mostly G/2 +12 or so) and this is a lesson I still need to learn.

I always immediately put my games into Hiarcs 10 and study the missed tactics. When I lose, it is of course due to missing my opponent's tactics. When I win, it's because they've missed mine. But that amazes me is the nature of the tactics I miss even in games that I win:

My opponent just played d5, failing to see my reply of Qc5+, winning the pawn. But look at what I missed after winning the pawn:

I played Qc1+ and went after the h2 pawn, a fine plan. However Bc4 wins the queen! It's incredible the number of such tactics I miss, and I've spent some time trying to understand why I miss them.

Typically the reason is because I'm already focused on some other target, and when my opponent doesn't stop me from going after that target I fail to see what new target might be even better. It's a common failing and stems from not reassessing the entire board after every move - something I've told my green-band chess kids more times than I can count.