It is in the middle parts of the tournament that we need to build our stack gradually by employing selective aggression while keeping a close eye on the ever-increasing blinds in order to not let ourselves get blinded out of contention. At the same time, we will be forced to gamble versus short stacks, keep a close watch on our opponents’ tendencies and strategies, make sure that we steal enough blinds to keep our stack healthy while not letting other players steal our blinds too easily. We also have to be prepared to make re-steals preflop with any two cards to keep aggressive players in check.
Does it sound complicated?
It is. The middle phase of a poker tournament is probably the most difficult and complicated of them all. The average stack will often be at around 20-30 times the big blind. Preflop blind stealing and re-stealing become evermore important aspects of the game. So - what general pointers are there to give?
If we have a big stack, we can allow ourselves to be more liberal in stealing blinds. Smaller stacks know that they are forced to risk their tournament life in order to go up against us, which makes them more prone to fold. Of course, we should still be careful. In the middle phase, a tight strategy is an absolute must. We simply cannot afford to open too many pots, since other players will catch on to this and re-raise us preflop, forcing us to fold, thus slowly decimating our stack. When having a big stack, our goal is to steal blinds or make well timed re-steals to keep on acquiring chips. We will stay out of big pots with other big stacks involved (unless, of course, we have a good hand), but we can gamble a bit against short stacks.
The same applies for an average stack. When having an average stack, we cannot however apply the same amount of pressure (since even a smaller loss would substantially decimate our stack), therefore we need to be even more passive and selective. In early position, we will often fold low pocket pairs and the like. In late position, we will be very careful with what hands we raise with. Yet, we still cannot become too passive and let our stack get blinded away. Mid-game poker is a fine balancing act, and the only way to get really good at it is to practice. With experience comes knowledge.
As for short stack poker (10xBB or less):
As soon as our stack drops below 10xBB, we need to get moving. We will wait for a decent (AT+, any pair) hand and go all-in pre-flop if we are first in, hoping to steal the blinds or to double up. If we start approaching 6-7xBB, we need to push any two cards when folded to us in late position, or else we will get blinded out of the tournament. By pushing, we at least give ourselves a chance.

Written by Andris Kangeris for 24hPoker.com