When you play sit and goes the decisions you make is much depended on the tournaments structure. If you are playing a full ring SNG (10 people) game with slow blinds(5 mins or more) and the blinds are low, you will need a great hand to put all your chips in, hands like AA, KK QQ and AK.

When i play those types of SNGs and i dont get that monsterhand my tactic is to get more aggressive in late position and try to steel blinds when the blinds are higher.

The games i like to play is 6 handed and when blinds increase faster (3 min blinds or less). Here you can get alot of chip if you rasie alot when blinds are higher because you need a better hand to call an all-in then to go all-in with. A good rule to remember is to not let your chipstack get lower then 3-4 times the big blind. What i mean with that is: if big blind is 100 your stack should not be lower then 300-400. If your stack are getting that small you should push almost every hand you can. The exception to this rule is when there is another even shorter stacked guy/girl on the table and you are one place to getting in the money.

This rule applys alot in double or nothing SNGs. If you are 3rd in chips and 3 people will get paid in the SNG and there is 4 players left and one guy has a really small chipstack, you shouldnt gamble with the bigstacks.

The key in every sit and go is to raise alot of hands when blinds are getting higher and dont be shy to go all-in preeflop with hands like a9 a7 kq kt qt qj etc when blinds are high and the table is getting shorthanded. Better to gamble with your chips then posting blinds untill you are out.

Good luck.