04-14-06 [poker]One thing I have to remind myself of all the time is this meta-principle : any time you have a truly tough decision where you can't figure out what the best move was - it doesn't matter. That's assuming it's actually a tough situation, not that there was a clearly right move and you can't see it. That is, if two or more moves have almost identical EV, then just pick one and don't agonize about it. Oddly enough, these are the very hands that I tend to agonize over the most.
Say for example someone pushes preflop you know they push with only AA or 22. Eg. they have the nuts or are bluffing. You have JJ, do you call? The answer is it basically doesn't matter. You might fold and they show 22 and you feel awful, or you call and they show AA and you feel awful, but it really didn't matter. More realistically this happens a lot when you put your opponent on a range and the optimal play against various parts of his range are slightly different. Like if you have a set on the river and you read that he either has a busted flush (you should check to induce a bluff) or a weak pair (you should bet small to get a crying call). If he has one or the other, just pick one and it's not a big deal which one you picked.
All of these "hard" decisions have a very tiny affect on your long term results (though they tend to be the hands that have a huge affect on your short term results). So, don't agonize over them, and worry about your actual important big mistakes. Eliminate the hands where you look back and go "omg, what was I thinking? that's just awful!?"