Natural here.
Take in a truck load of carbs. If you're natural, carbs are the most important aspect of diet. Without them, forget about size, unless you're a genetic freak.
Stick with compound movements. Forget cables, forget machines and work in a rep range of 4-8.
Foremost, have patience. If you're looking at a 6 month miracle, forget it, you're wasting your time. Be patient and the gains will come.