When pulling off a squeeze play there are several factors that you will need to evaluate before deciding whether to “pull the trigger.”
Factor #1: Who the initial raiser is – knowing the tendencies of the player who opened the action is important. While it is true that doing a squeeze play when the initial raiser is a conservative, tight play might not be the best move, this isn't necessarily always the case. It is their conservative, tight nature that might make the play even better than against a different type of player.
A rock in this situation might fold a hand as strong as jacks, queens, or a big ace not wanting to “take their chances.” So don't automatically discount making a squeeze play if the original raise comes from a rock. On the same token, if the initial raiser is a maniac, or a savvy Internet player who doesn't ever give a re-raise in this situation credit, then you need to only make this play with a legitimate hand.
Also worth noting is the position of the initial raiser. If they raised from early position, unless they are open raising an absurd number of times they should be given credit for having a legitimate hand.
Factor #2: Who the caller(s) is – most players that call a raise do so because they want to see a flop and are speculating; most of the time these players will quickly toss their hand into the muck if a squeeze play has been made. However, there are tricky players who like to flat call raises with big hands in these situations with the sole intent of inducing a squeeze play. These are obviously the players you want to be wary of.
Factor #3: Number of callers – there are two trains of thought on this one. First, the more callers there are, the more profitable the squeeze play is because of all the extra money in the pot. Second, the more callers there are, the more likely that one of the players will have a legitimate hand and one of them will look you up. This is where your observations of the players involved in the hand will be crucial.
If the players in the hand are weak, passive, or tight and will fold to adverse pressure, then raise it up. If you know there is no way they will fold, then don't squeeze unless you have a legitimate hand. If you do have a legitimate hand, this can be a great opportunity to win a huge pot.
Factor #4: The strength of your hand – you don't always need a hand in order to pull off a squeeze play, but having a hand can be the best time to do so because of the very nature of the move and the fact that it will not always be believed. If you have a big hand like aces or kings and there has been a raise and a call in front of you, re-raising can lead to one of the original players putting all their chips in the middle.
The Main Holdem Strategy Index: The Great Game of Holdem