Principle 1 Use Supreme Technique
Using the most optimum exercise technique for any lift is more important than any load, associated dietary regime or supplement, or even emotional state. A great diet, lots of sleep and good routine won’t make up for improper form.
If you don’t know how to properly perform an exercise, get help from a qualified professional. I can guarantee you that non-gainers routinely have lousy lifting technique.
Many bodybuilders/lifters cannot do certain exercises because of training injuries due to poor technique. Once more, poor mechanics (even at a controlled speed) is still poor technique. Squats, deadlifts and Olympic lifts (pulls) require great attention. Learn how to train and lift right!