Considering a tournaments have nine to ten players you can begin to narrow down your competition rather quickly. It is very likely that five of the players at your table will be average at best and have very little chance to win the poker tournament. 
Play a tight-aggressive style during the first few levels and let others do the dirty work unless I have a premium hand.
The reason for playing so tight early on is that it is very likely you will encounter players that will push all-in with any pocket pair. It is simply the nature of play in single table online casino.
When you get into a finals turnament stage , like any other final table sans the levels are a bit shorter. At this point you play to your stack size. Typically, single table Sit n Go poker tournaments only pay out the top 3 players. So playing to just “make the money” has absolutely no appeal. You need to play to win the tournament! If your short stacked then you need to gamble with hands like [J][T], [A][X], [K][X] and small pairs.
If you have accumulated a nice chips stack and are in first or second place then give the blinds a stab and see how they react to you. Pick on the short stack and steal their blinds as often as possible.
So play hard and be smart. If you can do those two things along with executing fundamental poker strategy you will do just fine.
Good luck!