Is there defesive cooldowns that I should be using (I already use Force Wave
There are very very very few situations where you should use force wave. Too many sages at 55 are using it, knocking mobs out of AoE circles that would kill them, and spreading trash out making it more difficult for tanks to generate AoE threat on them. Yes, Force Wave can be talented to heal, and in some situations it is useful (although I don't spec into it), like when all the ranged DPS are stacked or it's a boss fight that is immune to knockback. But on trash pulls or as a defensive maneuver, it actually causes more problems than it is worth.