Whats the best way to gain muscle? Without...?

Whats the best way to gain muscle and have a good muscle to fat ratio without using steriods, creatine? I dont want too look too bulk I want to look more defined. I have a slightly high metablosim and whats the best way to equal out my metablosim to allow my body to store more fat and creat more muscle. I am a very active person I am just looking for others insight on diet, exercise.. I do not smoke, rarely drink, dont do any other drugs. I want natural ways in doing so..