I played sng's for a while and found them quite easy. Here is my basic sng strategy. It is MUCH tighter than most. It also gets in the money about 60% of the time. I focus on tight agressive play early, and becoming almost hyper agressive on the bubble and when you get in the money. This strategy is not perfect or complete, but it worked for me through $5 sng's. If you like it, try it.
Avoid turbos at all costs. The swings are bigger (for me).
Early levels -
super tight in every position. raise 3bb all pairs and AK (it is ok to fold 77 and under in the early positions if you want) (if players are bad, raise more with AA and KK)
Reraise and be willing to get all in QQ+ and AK unless a super tight player is raising, then fold the QQ and AK. Feel free to raise big at low stakes, you often get called.
In late position I just call raises, with 22-JJ.
If 2 or more players are in the pot for 4bb or less, call with suited connectors and Ax suited in the blinds or late position. (0f you are playing less than 30bb, do not call sc or AX suited)
Fold everything else, no matter how pretty it is.
After the flop, if you are the agressor, bet 2/3 pot to pot.
Turn and river require hand reading skills, but do not get there without the best hand if possible. If you have a big hand, and are not likely to be behind try to get all in, especially on the turn, when the idiot chashing a weak draw still thinks he will get lucky. If at any time you feel you are behind - fold. Never chase in the early stages of a sng. You cant win from the rail.
Mid stages -
usually 1/2 of the field is gone at this point. Your primary goal is to get in the money, so avoid difficult situations. If short stacked (<30bb) play big pairs and AK very agressively. I would almost always raise 22+ at thit point with 20bb or more. If you get raised with JJ or less fold. Yes, it feels weak, but you cant win if you are out of the game. Most players will reraise you with TT+, AJ, AQ, and AK. You will not be a big favorite if the money goes in with less than QQ. Like earlier folding AK and QQ to NITTY players is ok.
It is also time to steal. any 2 cards Ten or higher on the button, and any otherwise playable hand is worth a raise of 3bb. If the blinds are frequent defenders you may need to play tighter than I suggest, or be ready to go to war with a modest hand. I prefer tight with a small stack and loose with a big stack.
If you have a big Ace or TT+ reraise to defend your blinds, fold AQ, and <QQ to all in if you started the hands with more than 20 bb.
If you are the chip leader (often he case here) open raise very often with any 2 high cards, any pair, and on every button. If somone else raises and you are not in the blinds, fold all marginal or weak hands.
If you are a medium stack, look to raise whenever you think you can steal. Contimue to play good hands agressively.
If you are getting short stacked: 2 strategies I employ depending on if the players defend or fold their blinds.
1. Defenders: look for hands you are willing to get all in with and shove them. Hands like AJ+, JJ+ and if on the button, or in the sb (1st in) any 2 high cards, just open shove. I also add suited connectors from 78s up on the button.
Folders: Min raise the above hands, and small pp. Fold weak hands to action. If you get below 12bb revert to above stratagy.
in both cases remember you want to get in the money: so do yuor opponents, many become passive: this is where I turn up the agression.
Late stages, in the money and all or 2 players are short stacked with high blinds.
Small stack: I use the same strategies as short stacked in mid stages: be more willing to shove any big Ace, 2 broadway cards, and any pairs. You will lose here unless you can steal often or double up.
Medium stack or chip leader: use your stack as a weapon: raise every Ace, 2 big cards or pair. Raise every button. If unopened, raise every sb (unless BB likes to shove defend). Be willing to 3bet and 4bet all in with any hand you would consider calling if a short stack enters the pot because losing 10 bb is not much worse than losing 4bb. You may get some bad folds as well.
If I can get away with stealing with min bets, I will because they represent a good portion of the short stacked players chips.
Heads up -
At this point I have a goof feel for how my opponent plays the game. If he is tricky or observant it is time to get creative. I'll leave that to you. Against many players, I just raise every hand until he reraises. I then fold weak and shove strong. Dont forget to change gears as soon as your opponent seems to catch on to your plan. If blinds are really high (effective stacks <12bb) I shove every playable hand. Sometimes every hand. It is amazing how often people fold. If they call, you are often a 2:1 dog. That is not that bad.