I'd concentrate on compound movements like squats, deadlifts, bench press, bent over rows etc. That's not to say don't do concentration exercises.
As for diet, at this point, you need to eat a lot of solid food, steak, chicken, ground beef, oatmeal, rice, potatoes. Eat something every 2-3 hours. You are going for size and since you have a fast metabolism, you shouldn't concern yourself too much with getting fat.
What is your diet like now?