Besides a player's betting patterns, I think you should take into consideration where they are seated at the table. For instance, if everyone folds to the button, and he raises it substantially, it usually implies he's trying to stick it to the blinds and steal the pot. Even if they have a decent hand, it's much harder to call than make a bet, especially when out of position.
Along with that, try to figure out if they are tight or loose. If a tight person suddenly wants to bet it is a good sign to get out of the way, while a loose player is nothing to get too worried about.
Are you using a HUD?