There are certain times when you need to bet or raise very, very aggressively before the dealer even lays out the flop. If you have two aces, two kings, two queens, or an ace and king combo before the flop is dealt, that is when you need to be aggressive. This is because these particular cards can often lose their inherent values when the pot is large and there are multiple players in the game.
Sometimes, you need to be very careful and even moderate when you are betting and raising for the flop. You should be somewhere in the middle if your starting hand consists of an ace and a king, an ace and a queen, an ace and a jack, or a king and a queen.
Lastly, remember that you should only raise two jacks when you are playing a tight table, because it will run out those hands which consists of aces and nines, and things of that nature. You should probably not ever raise on two tens.