Phil Gordon gives some great online poker secrets in regards to how to play when you are the big stack at the table in a poker tournament:

1. Never limp into a pot
2. If the blinds consist of tight players with average stacks, play almost any hand in position
3. Punish limpers with big raises from position when you think they are weak
4. Call from position more often when an opponent with an average stack enters the pot with a raise
5. Rarely, if ever, confront a short-stacked opponent without a premium poker hand
6. Try to win more hands before the flop

In online poker, it’s important for you to always have a reason why you are putting money into the pot.  Here are some good options:

1. to steal the blinds
2. To isolate a player when you are in position
3. Because you think you have the best poker hand
4. To set up a delayed steal
5. Because you believe if you make your hand, you will be paid off better (Implied Odds)

Sure, getting great hands helps – but on top of having a great poker hand, you need to find the best situation to play them.  Pay attention to your table.  Find the situation and the players that you can best take advantage of.  If a player just lost a big pot and raises - take advantage of his thoughts.