As the play becomes short-handed and the stack sizes decrease relative to the blinds, this is when the tournament is won or lost. Depending on how the early game went, you will now have to adapt your game according to your position and chipstack. With less than 15 big blinds you should effectively be in push or fold mode. If you have a bigger stack you can make small raises and reraise other players all-in with some degree of fold equity. If you’re the big stack you need to dominate the other players by hoovering up the chips, but you also need to know when to draw a line in the sand if other players start shoving on you lightly.
Of course, you need to assess the dynamics of each situation individually. Pay attention to the vital stats of the game: how many big blinds you (and your opponents) have, how many players remain and how much a round costs you (based on the number of players left and when the antes come in). By weighing up these numbers you then have to make the best plays based on your cards, stack and position.
Make sure you change gears and play progressively more hands as players go out and the blinds increase. This will also depend to a large part on the tendencies of other players, so stay observant. Good players will loosen up later in the game so you can re-steal or call lighter against them, whereas if you’ve identified any overly tight players you should take advantage of them by continually stealing their blinds.
Closing it out
Once you find yourself playing heads-up, stack sizes will still determine what moves you can and can’t make. However, bear in mind that against one opponent you need to play a wide range of hands to avoid getting run over, and that you can push very lightly from the button with a short stack. For example, with ten big blinds shoving hands like J-3 suited or 9-7 offsuit is standard play, and with deeper stacks you should make a standard raise with almost any hand from the button. As long as you keep up a high level of aggression you will always stand a reasonable chance heads-up.