to very quickly dodge, stop and reverse, try tapping the jumpjets (making you do a little hop), and when you land, hit reverse. You will stop instantly after the jump, and start reversing.
Much faster then hitting X, and then reverse. (also has the bonus of making the enemy think you are going to start a big jump, spoiling his aim).
When having multiples of a particular main weapon (6x CERMBL / 4x CERPPC), bind the left-arm ones to the left mouse button and the others to the right mouse button. This way, you can shoot "around" corners - keeping most of your mech hidden.
Learn (via the wiki) what are the weaknesses of mechs. For instance, the NovaCat has 12k Center Torso armor, but only 5k in the arms and legs. More efficient to arm a novacat than core the center torso. Or leg it.
The warhammer, on the other hand, has 8k in the CT and 7k in the legs, making legging a bad decision for this particular mech. (arms have 5k).