I worked out hard for a year and gained 15 lbs (up to 160 lbs now). I was never able to gain weight before. I took creatine, protein bars between meals, NO2 and 1-1.5 gallons of water a day. Sticking with a routine helps out a lot. Seeing results makes you work harder and harder! I'd like to hit 170 lbs and I'm 5'11".
-Victor