Tight is right at the beggining, but you also want to be able to increase your chips to aground 2x, 3x the average before the break, since the blinds will eat you up ( talking about speed tourneys here).
I usually rebuy at the start so I can have a good stack for double-up. Look out for your opponents and what they push with, cos usually there are a few donks that go on tilt very early on.
I also go preflop allin with speculative hands (KT+, A9+, 55+) if there are more than 3 players in the pot and my stack is around the double rebuy. This way you have a chance to quadruple up, and if you lose you still have the same stack after the rebuy.
Do not wait only for good cards, since you will often be in a multiway pot with your chances to get cracked increasing. Try to use the position, and push the small stacks around as mush as possible.
After the break, it depends on your chpistack really. If you are shortstacked, you must push any Axs, PP, even Kxs or two broadways. If you are deepstacked, try to steal as much as possible when IP, and fold low PPs and suited facecards from early.
Once you get to the final table its anybody's game really.
Gl,