The essence of short stack play is that you play a very conservative style and essentially only play before the flop or on the flop. Loose players gain more of an advantage on the turn or river, when they can capitalize on their wacky draws and because their ranges are less defined, so the short stack defeats this advantage by being all in at this time. You have a lot of profitable opportunities to squeeze dead money without risking a ton. For example a guy raises, who has a strongish range but wide enough, and you get five loose callers. You have an okay hand like 99. You stand to be in okay shape against the initial raiser some of the time and there is lots of dead money. SO let's say the raise is to $15. If you can jam here for $80 in total this is a great spot because there is $90 already in the pot and you stand to be competitive, say 50/50, against the initial raiser. So you stack off that is about $45 profit. But if you have say $400 stack and you raise to $90 and you get re-raised to $400 now you are probably in bad shape and have to fold. Of course it works just as well with even stronger
hands like AK, because now you are actually well ahead of the preflop raiser and are essentially just collecting the $90 in the pot, or getting it in as a 2:1 favourite.
Obviously knowing how to play a short stack intelligently is the key. There is no question that playing deep stacked in soft games can be even more profitable as if your opponents are going to make big turn or river mistakes then you want to be able to capitalize on them. Usually I do a mix of short stacking and deep stacking. I like to short stack when I first sit down at a table and am figuring everyone out. Initially, my opponents and I are on a closer to even footing. As the game progresses, I watch them carefully and begin winning the information war. After an hour or two, when I have a good grasp of game flow mechanics and a deeper understanding of how my opponents play, I will be much better positioned to ascertain the most profitable stack size. Another important consideration is that you cannot take money off the table but you can always add on (up to the max) if you determine it would be more profitable to be deeper.