Use heavy negatives on the dip machine for triceps. I absolutely love doing these. It's an effective, safe way to overload your triceps with heavy loads.
Have someone help you do the concentric portion of the lift. Then do the eccentric or negative portion by yourself. Take a few seconds to lower the weight.
The central nervous system - it's been called it the "last frontier of weight training." Regardless of whether it's the last frontier or not, it's mucho important. Knowing how to manipulate it can accelerate your progress almost beyond belief, regardless of whether you're a competitive athlete or a bodybuilder.