Okay heres the deal.
no matter what your body type(slow metabolism, fast metabolism), no matter what your goal is(build muscle, lose bodyfat), its all about protein. every meal you eat from no on is based around protein. this is never going to change. whether your dieting or bulking, whether you have a base metabolic rate of 1200 cals a day or 3500 cals a day.
what deviates from this base rule is your amount of ENERGY calories that you will take in at every meal, every day. energy calories are FATS, and CARBOHYDRATES. do not be scared of either of them. you need SOME fats and SOME carbs everyday. if you have a fast metabolism, you will need a good amount of both, and you might need them at every meal. if you hav a slow metabolism, you will need a small amount of fats everyday, and you will be best off by "cycling" your carb intake... that means you go one day "high" carbs, one day "moderate" carbs, and one day "low" carbs. then repeat. again, what "high", "moderate", and "low" actually describe depends on your metabolism, if its a workout day or not, and what your fat intake is. with minimal fats, an average metabolism, and a workout scheduled....your probably going to get aroound 250 grams of carbs on a "high" day, about 150 carbs on a "moderate" day, and on your "low" day you should probably stick to <50 grams of carbs...(excluding vegetables.)
TIMING is of the greatest importance. eat protein EVERY three hours. eat some fibrous vegetables like broccoli or green beans or lettuce every time you eat some protein. as for your energy calories(fats and carbs), you should space them out evenly, or even better, stack them into two areas where they are needed most= early morning and post workout.
good sources of protein are= whey. boneless skinless chicken breasts, lean red meat, tuna, wild salmon, egg whites, and turkey.
good sources of carbohydrates are= sugar free low fat oatmeal, brown rice, and whole wheat bread&pasta.
good source of fats= fish oil. flax, almonds, sunflower seeds, avocados, olives, and sometimes all natural peanut butter.
lots of water. lots of water. lots of water. when you get a craving, go wild on fibrous vegetables and lean protein like boneless skinless chicken breasts.
as far as workout supplementation, drink a whey protein shake before, during, and after your workouts. you only need about 10 grams per serving. buy some creatine monohydrate if you can, and put 5 grams into each of those shakes. if you have a fast metabolism, youd do yourself good to throw in some waxy maize carbohydrate into those shakes as well.
you need a solid multi-vitamin, if you can afford it "animal pack" really is a solid product thats worth the money.
other than that....kick ass in the gym and get as much sleep as you can.