[Doc]

Kiko.

My thoughts. Alien is well worth listening to on these matters too.

Most tournaments (single or multi-table) have similar characteristics in some respects.

I'd define 4 phases:

1) Avoid the numpties. Lots of all-ins and general loose play. During this time you don't in general want to get involved unless you have a great hand (or great potential) AND position. Good players will play very few hands IMO. Typically in STT this lasts for two or three rounds of the table.
2) Early/middle phase with many of the lunatics gone - although there will be some with big stacks. You now need to build your stack so you have to loosen up a bit and look to steal some blinds. Others may be doing the same, so be careful. Watch out for any remaining numpties who will still be playing fast and loose. This probably lasts till about 6 players are left in an STT.
3) 'Bubble' - at this stage people are close to money and often the table tightens. This is a good chance to get aggressive, especially if you have a big stack. If you do, you can really bully the table and build your stack quite large. People are afraid of going out and don't want to take risks. Be careful though of very short stacks who will have to take risks. Pick on the middle stacks here. This will last pretty much till you're at the money stage - i.e. last 3
4) End-game. You have to loosen up a lot now as so few are in and the blinds will be so big. Your chances of winning are largely determined by luck, stack size and skill in that order. You can't wait for the nuts - you have to get out there and gamble.

If you're losing from chip leader position then maybe you are being too loose. The other thing is not to be timid. In a tournament you have to take stands, you can't wait around. Say you raise with pocket kings and get re-raised. An ace comes on the flop and you are first to act. Of course the other guy could have an ace or aces, but you still want to bet. If you check-call you've shown weakness and he'll take you on again. If you check rasie you may be risking extra chips, and if you check-fold you may be mucking the best hand. Use your stack and if someone takes you on - go for it, unless you have very strong reason to fear you are beaten. The other thing to remember is that as numbers drop, high cards become more important. You need be less worried about middle straights and flushes. You may lose out occasionally, but you'll win more often than not.