How to play at the start of a tournament

The optimal early stage strategy is in great lines similar in every type of poker tournament, yet there are some subtle differences between low blind MTT, SNG and freeroll play.
The common denominator among the early stages of these three types of poker tournaments is the TAG approach. Being TAG (Tight aggressive) makes perfect sense from several angles. From a mathematical point of view, the small blinds (small compared to the size of your stack that is) call for a tight approach. The smaller the blinds are, the tighter you should be. If you ever read Sklansky, you know that that's because of the pot odds, which only justify making a move on the very best starting hands. Basically, with such small blinds, you'll be risking a lot to win a little every time you make a move.

From a non-mathematical perspective, being tight in the beginning of the tournaments (and exploding on good hands) is correct because you need to protect your stack. Playing on a finite stack means that you won't ever be able to reload if you lose: when your stack runs out, you're done, you're removed from your table and there's no way you're ever going to right that wrong later.
In a tournament, your stack represents you for all practical purposes at the table. It is your life-blood. The bigger it is, the stronger you are. The interesting thing about it is that in the same time, your stack is also the only weapon you have at the table. As long as you have a big stack, you can intimidate opponents and you can felt other large stacks. Upon the sight of your stack, people will think twice about tangling with you, because every hand they commit chips on against you may well end up being their last one.
The stack keeps you alive but it also gives you the power to dominate and to forward your cause.

Playing ABC TAG poker is the best way to preserve your stack early on and to add to it too, making sure that you'll have a large stack compared to the blinds in later stages too. This is what experts call optimal play. You feel no pressure and you do your best to chip up, while keeping your stack shielded from harm. When you pick up a good hand, you strike and you strike decisively. Being tight doesn't mean you should fall asleep.
In a freeroll tournament, this is where things become a little more complicated. While you may approach the freeroll the same way you approach a real money buy-in MTT, other players may not do the same for the simple reason that they do not have an actual investment riding on it. As a matter of fact, it's pretty certain that you'll bump into several players in the early stages who will shove all-in left and right, not giving a damn about starting hand selection, position or anything. On one hand, these people do represent a nice source of chips, on the other hand though, you need to approach them carefully because of something called the "shooling" effect.

If you shove all-in on your pocket rockets against 4-5 callers, your odds will be pretty flimsy, because of this schooling (because there will 4-5 drawing hands going up against yours). What you need to do is to isolate these fish. Stake out your victim, separate him from the safety of the herd and then strike. There will be bad beats, but this approach is almost guaranteed to take you deep into the freeroll.

Don't forget to sign up for arakeback deal too. Rakeback deals, like the ones you'll find at Rakemeback,
offer you rebate on your tournament fees, thus significantly decreasing your losses. Playing without rakeback is like willingly accepting a handicap:
don't do it.