The biggest mistake players make when playing out of the blinds is in how they defend their blinds. Without question, the best way to defend your blinds is by re-raising. Because you are out of position and last to act pre-flop, you want to apply maximum pressure to the other players. This helps to not only define their range of hands and take control of the hand post-flop, but it gives you an opportunity to win the pot outright.
The best players to defend against are those that are raising from typical steal positions. Normally, a person raising first to act from the hijack, cutoff, button, or small blind are not raising with a legitimate hand. They are raising in the hope that you will fold your hand and that they will pick up the blinds.
Stealing the blinds is how many poker professionals make their living. They feast on the weak who relent time and time again every time their blinds are raised. Make sure you are one feasting, not the one getting eaten alive by raising from the blinds at the right time
What raise amount is the best one to make when defending?
Whatever amount will induce your opponent to fold and one that makes sense for the hand that you are trying to represent is what you should look for. It doesn't make sense to move all in pre-flop if you have 60 big blinds. Your opponent is going to know that you aren't doing this with a big hand and you are just trying to induce them to fold, and this could see them look you up with as marginal a hand as A-10.
Raise the amount you would raise if you were raising with a big hand. The key is to make the story believable. Most good players will sense a bluff if the story of your hand does not add up, so make your response to their aggression seem a convincing representation of a big hand.
The most important thing to remember when defending is to be aggressive, but to be smart about your aggression. Fold and call when it makes sense to, but if you truly are considering playing a hand out of the blinds, especially in a raised pot, your best course of action will almost always be to raise.