The relative strength of your hand is very dependend on your position on the table.
Especially in early position you have very little to no information at all about the hands of your opponents.
You have to ask yourself the question if your hand is strong enough to call a raise or even strong enough to reraise.
When you decide to enter the pot it is a good idea to raise because:
1. Your opponent knows you have a strong hand.
2. Eliminates weaker opponents
3. Gives you the lead in the hand
In the early stages of a tournament, limit your early position starting hands to only the strongest range of starting hands. Later in the tournament you can open up your range because players are more likely to fold.