The key building muscle mass is to eat, eat, and eat some more. 99% of the people who call themselves hard gainers are really just under eaters. A lot of guys will skip breakfast, have a small lunch or snack during the day, then pig out and stuff themselves at dinner and think that they are eating a lot.
You need to eat something every 2 hours during the day to build maximum muscle mass. Eating frequently will make eating lots of food much easier.
When you want to build maximum muscle mass you should aim to eat 1.5 grams of protein and 25 calories per pound of bodyweight each day. Don't just stick to low fat "diet foods". Eat everything! You need lots of calories and it will be too difficult to eat a high calorie diet with just low fat foods.
Protein drinks are a great way to get extra protein and calories in your diet. I suggest that you use the big 5 pound containers of whey protein powder because these are the best value for your money.
When bulking up you should aim to eat at least 50 grams of protein and 1000 calories each morning for breakfast. This will start your day off right for maximum muscle building. It really doesn't matter what you eat, just as long as you eat. If you are in a hurry you can have a big protein drink, 2-3 slices of toast with peanut butter, and a piece of fruit. Or if you have the time you can cook up steak, eggs, hash browns, pancakes, etc.
For lunch at work or school you can cook foods such as chicken, beef, turkey, rice, pasta, etc. ahead of time and put them in a Tupperware container to reheat in the microwave. Make sandwiches such as tuna, roast beef, turkey, etc. Mix a protein shake and take it with you in a thermos or shaker bottle. Take a protein / meal replacement bar. Take fruits and vegetables i.e. apples, bananas, carrots, etc.
For dinner you can eat basically any meat and potatoes type of meal. Get some cook books and lean to make some good mouth watering meals. The tastier you make your meals the easier it will be to eat the volume of food necessary to build maximum muscle mass.
Good snacks to eat during day include dried fruit and nuts, cottage cheese, yoghurt, cereal and milk, fresh fruit, protein bars, and protein shakes, etc.
If you are really serious about making solid muscle gains, as well learning how to sculpt that raw mass into a lean and muscular physique. I highly recommend that you check out my Bio-Genetic Weight Gain System.
You won't be floundering around with your workouts wondering if what you are doing is working or not. You will have a proven step-by-step plan showing you exactly what to do to get the body you want.
Training is a sheer pleasure when you get results quickly. You no longer see your workouts as drudgery or hard labor - it becomes fun, exhilarating and incredibly rewarding. When you look in the mirror and see your body change day by day, you'll feel like you're on top of the world!