When you are playing tournament poker, be it online, live or speed poker, your stack size is going to dictate a lot of your decisions on the felt. 

There are two stack sizes that are very easy to play. The first is a 1-15BB-stack size, because your only decisions are all-in or fold. The second is a monster stack size because you have enough legroom to be a little bit more creative without fear of being eliminated. But what about the bit in between?

The 16-20BB-stack size is a tricky one to play at Poker tables, but one that can easily be mastered with a little understanding.

Firstly, do not open any hands that cannot stand a three-bet. Opening and folding with a stack size of this nature is a mistake, because your chips are precious. 

The only time you should vary this advice is if your opponent is very weak and only three-bets with the top end of their range. In this case, there is an argument for open folding from this stack size.

When you hit a stack size in this range you should be looking for good spots to three bet, rather than being the first player to enter the pot. This is because of the reduced post flop action as a result of your stack size. 

Make diligent notes so you understand which players are open folding from stack sizes of this nature, then three-bet them with impunity. 

Also try to recognise the players who understand stack sizes from those that don’t. If you see a really good player open raising off a stack size this big, then you can fold everything but your very best hands, safe in the knowledge that they are setting a trap with a monster hand.