1) One of the big differences of playing in a tournament is that you need to pick you hands carefully. Spend most of your time throwing your cards away at the right beginning. If you see that your cards won't amount to much, fight the urge to exchange most of them, and just hand them all in. This is what most tournament players do anyway. If you don't believe me, watch the others play.
2) Money you take with you to tournaments lasts for a much lengthier period than when playing with friends or online. This is one of the advantages of not playing every hand you are dealt. (Hint: You should do the same thing when playing with friends even though that then becomes boring.)
3) Do not sit to the left of the dealer. Ensure that there are at least two players between the dealer and the players to the left. Why? Only the first 2 players seated on the left of the dealer have to place the ante. Since, most of the tournaments involve ten players on each table, you save this much each time you play. This also means that each hand that you fold will mean that you have spent only half that of the lower limit. This amounts to three dollars in a two to four dollar rake tournament.
4) Take into consideration that the mere fact that you are away from home means that you will spend money on food and drinks. Try and get your own, but in any case keep it light.
5) Tournament dealers are not paid much, and so it' general practice to give them about three percent of whatever you win. Consider that all gambling halls and poker rooms also take a certain percentage but at least this comes from the money you win and so you don't feel it.
6) One of the other advantages of playing in a tournament is that you can use more money than you had. For instance, for a hundred dollar sit-in, many casinos and poker rooms will give you about five hundred in tournament chips to bet with.
7) If high odds and high risk is not what you are looking for you can take advantage of the late night satellite tournaments. These generally begin at one in the morning and since the number of players won't be high, you stand a bigger chance of winning.
Conclusion: Playing poker requires tremendous skill as well as come luck. While you cannot depend on luck, improve your skills and your online casino or other kind of betting account will show a profit.