1. Nothing. It's all genetics, and you can't change that.
2. An expensive potting soil that doesn't have fertilizer already in it, mixed with about 20% perlite.
3. Sounds fine. Be sure and read up on lighting, about proper wavelengths for different stages of growth, and other stuff. Of course the more light the better, within reason. You can have just a few proper lights do the same thing as many bigger improper ones.