If you've looked into it at all I'm sure you've been drilled with the idea that you need to *eat eat eat*. Well when I first started looking into it I realized that I barely ate at all. Maybe your typical school lunch, dinner, maybe a snack. Combine that with a high metabolism and you are getting nowhere fast.
I started out just eating small things to fill in the hours and that kept the metabolism at bay, I guess. If you want to get bigger you have to eat bigger and LIFT BIGGER WEIGHTS. Use a protein shake in the morning afternoon and evening... better yet - whenever you feel a tiny tingle of hunger. Just keep a power product somewhere, get a shaker, drop in a few scoops, add some water, shake it up and then drink it. The whole process takes about a minute at the most and there really isn't an excuse not to do it. Plus you need to WORK OUT 3 times a week. If you don't have a gym that's fine but at least do something with your body (i.e. pushups, pullups, lift a dresser, move tables, whatever) so that your hard earned calories aren't put into (entirely) fat. If you have the time to cook or always have leftovers in the fridge just EAT it. Rich in protein foods like chicken, beef, eggs are VERY good and I'm always adding these to my meals. Just a protein/weight gainer shake isn't going to cut it, but it will definitely help.
This could be different for everybody, but that's what it did for me. 35 lbs of muscle in about a year is definitely progess. In combination with a larger diet and my continued workouts, I plan to reach 185 by June. It's doable, you guys. Stay motivated and you'll see results in no time.