Looking for others trying to GAIN weight!

Options
I am a 20 year old college student that is trying to gain weight. Right now I weigh between 165-170. Eventually I want to be anywhere between 200 to 225. I have been working out for a long time, but I am new to eating correctly. I have a really really fast metabolism and recently I have discovered that I can eat more than I ever thought possible. I am naturally thin, but I am still muscular. I want to know if anyone can gives me any tips on what I should eat to try to build muscle and gain weight without getting fat. Any help would be appreciated.