Don't shy away from the tight strategy in the early stages, you only really want to play premiums until you lose a few players. You will very rarely find yourself building big pots post flop early on and winning them in 9 man sit n gos with the blind/stack ratio, and any you do win will almost certainly not see you through to the money either. You are best to sit back for the first few levels, learn to be handy with the notes instead of the call and raise buttons! There's nearly always enough donkeys waiting to knock each other out in the first few levels.
It sounds like you're not changing gears through the game, once a few players have gone, you really want to start opening your range, stealing blinds etc. make sure you pick out who the weak players are, with < 6 players left, you really want to be picking up these guys blinds, even if you are out of position, if the guy to your right has seen very few flops, raise his BB utg with a marginal hand. So many people just roll over as you approach the money. It's a lot more situational than simply raising with 'ace rag' or 'suited connectors' every now and then. Don't be afraid to defend your blind with a marginal hand either against an aggressive player, especially in the late stages. There is a good chance they may fold, and if you end up in an all in situation, you are likely to not be far behind and possibly be ahead either.
Try to aim to get heads up, rather than simply making, or rather folding your way to the money. When there are 5 players left (assuming 3 pay out), this is the time to really get aggressive, don't be afraid to take a coinflip here. The worst thing you can do is be pushed around and have your stack dwindle, because when you shove, you're not getting value. The bubble onwards again selective aggression is the key, and stack sizes really come into play shorthanded, google ICM (Independent Chip Model). The maths is complex, but if you get the hang of the concept, it will help your understanding.