Good soil, adequate lighting, ventilation, humidity, and temperature. Don't overwater. Use a good line of nutes (organics all the way), and most importantly have some common sense. Growing dope requires extreme patience too. If you don't have patience, then don't even think about growing.
If you want the best results, educate yourself beforehand and buy the best seeds, soil, lighting, and whatever else that you can afford. Some might disagree with this, but if you try to do a job with improper or inadequate tools, you're just setting yourself up for a trip down that long road of frustration.
Do it right, do it light. Do it wrong, do it long. That's what my 8th grade gym teacher always yelled at us and it's true when it comes to just about anything in life.
Good luck and happy growing.