I was 6'8" and 197 lbs, I'm now 6'-8" and 285 lbs. I want to start by making two things clear. First of all muscle mass doesn't come fast no matter who you are. But if you train hard and have patience you will have some amazing results. Second, this advice I'm giving you is based on my own experience so be sure to get advice from other people too.
Nutrition

This is the most important factor in gaining muscle mass. Remember this: IF YOU DON'T EAT MORE CALORIES THAN YOU BURN YOU WILL NOT GAIN MASS NO MATTER HOW HARD YOU TRAIN.

You have to prepare yourself to spend a lot of time cooking and eating food. The first 4 years I trained, I had very poor results even though I trained hard. I didn't know anything about nutrition, but when I started reading about it and applying it to myself, things started happening. Then I became very lazy and didn't put to much attention to my routine (I was in and out of the gym for almost 10 years). Until one day somebody ask me to be his bodyguard but my body wasn't in the best shape and I started doing just pushups and chins and over the next year I gained 45 pounds of muscle.

I gained a nice amount of muscle and I decided to join the NAVY (guess what? I lost almost 40 pounds of muscle) and with the same love after the first year in the NAVY I decided to start over again. Right now I look HUGE again, more stronger than never before, with more motivation and dedication than my early years in bodybuilding. Maybe your are asking how a 39-year-old keeps in shape? Simple, WORKING HARD.

Let's get started:

1. You have to eat more calories than you burn. Growth processes demand a lot of calories and you have to do this EVERY DAY. In fact this is where almost everyone fails when it comes to building muscle mass. Don't worry about getting fat. If you're skinny and training hard you will burn the calories easy.

2. How many calories you ask? As a rule you have to eat 20-22 calories per pound of bodyweight. Of course as you gain weight you have to eat more calories. So you have to figure out how many calories you eat now and adjust. Carbs/ protein/ fats should be 55/25/20%. If you don't gain weight, try to add 500 calories per day. If that isn't enough, add 500 more and so forth.

3. Eat 3 big meals plus 2-3 smaller meals each day, 3 hours apart. This is VERY important. First of all you have to eat 5-6 times a day to get enough calories. But even more important is the fact that if you eat more than 3 hours apart the body goes into a catabolic state, which means that it is burning muscle for energy!! This is especially true for skinny people. You don't want to happen, right?! Two sandwiches with meat or cheese will do for one small meal. Use your imagination. Anything goes just as long as there is some protein in there somewhere.

4. Your breakfast is the most important meal of the day. You have been fasting for 8-10 hours and your body is in a catabolic state (eating muscle) so you need to feed it with a lot of food.

Here is one example of my breakfast:

(I will post my actual diet in a future article)

Oatmeal, 16oz w/ milk
Protein shake
5 eggs (whole or just white)
French toast or Hot cakes (4)

That's it. If you have trouble eating much for breakfast you have to teach yourself to do it

5. Don't waste your money on all the fancy supplements you see in the magazines. It's your normal multi-vitamin/mineral tablets, your average whey protein powder, creatine and prohormones. Every day take a normal multi-vitamin/mineral that covers 100% off your daily needs. Then don't give it another thought. A protein drink can substitute one of your smaller meals. Eat some fruit, preferably 2 bananas, and drink a protein drink right after your workout. I do this myself because our muscles are like a sponge at this time and fueling right after a workout works wonders. I blend 60 grams of whey protein in skim or whole milk (don't be afraid of extra fat, you will need it) and bring it with me to the gym.

Training

OK, let's talk about training. I have made the best gains in muscle mass when I used the following program.

1. Be sure to write down your own program so that you can return to that program if my program doesn't work for you.

2. Remember that from time to time you have to change exercises and set/rep schemes to shock the body into new growth. I personally have some favorite exercises that I always use and the other exercises I change very often.

3. The program I use works for ME. That doesn't mean that it works for everybody else. Training each body part 2 times per week isn't very popular but I have found that working each body part every 4 days is the optimum way for me to train. I train on monthly cycles. The first month I train every other day half the body on the first day, rest day two, second half of the body the third day, rest on day four and so on. The next month I train 3 on, 1 off, training the whole body over 3 days then taking a day off. You can see I always train in 4 day cycles. The third month I go back to training like the first month and so on.

The reason for this is that it keeps up the training intensity and keeps me from burning out. If you train 5-6 days a week all year long, you at some point risk burning out or loosing interest in training. You'll notice that I like mid-to-high volume sets.


Training Program First Month

Training split 1 on, 1 off
Day 1: Chest/shoulders/arms
Day 2: Rest
Day 3: Back/legs/waist
Day 4: Rest
Day 5: Chest/shoulders/arms
Day 6: Rest
Day 7: Back/legs/waist
Day 8: Rest
And so on...

Day 1

Chest:
Bench press: 5x12,10,8,6,4
Incline bench press: 4x12,10,8,6
Dumbbell pullover: 3x15,15,15

Shoulders:
Military Press: 4x12,10,8,6
Bent over laterals: 4x12,10,10,8

Biceps:
EZ preacher curl: 4x10,8,6,5
Alternate dumbbell curl: 4x10
Incline dumbbell curls: 4x8,8,6,6

Triceps:
Pulley pushdowns: 4x12,10,10,8
Lying French press: 4x10,10,8,6
Close grip bench press: 4x10,10,8,6

Forearms:
Wrist curls: 3x15,15,15

Day 2

Rest

Day 3

Back:
Wide grip pull downs to the front: 4x15,12,10,8
T-bar rows or one arm dumbbell rows: 4x10,10,8,8
Pulley rows: 4x15,12,10,8
barbell shrugs: 3x10,10,8

Legs:
Squat: 5x15,12,10,8,6
Leg press: 4x12,10,10,8
Leg curls: 4x12,10,8,8

Calves:
Standing calf raises: 4x15,12,10,10
Seated calf raises: 4x15,12,10,10

Waist:
Crunches

Second Month

Training split 3 on, 1 off
Day 1: Chest/arms
Day 2: Legs/waist
Day 3: Back/shoulders
Day 4: Rest
Day 5: Chest/arms
Day 6: Legs/waist
Day 7: Back/shoulders
Day 8: Rest
And so on...

Day 1

Chest:
Bench press: 5x12,10,8,6,4 (Last 3 sets perform partials with heavy weight)
Incline dumbbell bench press: 4x12,10,8,6
Decline bench press: 4x10,8,8,6 ( If you have problem with your shoulders avoid this exercise and swap to Decline Flyes)

Biceps:
Alternate dumbbell curls: 4x10,8,6,5
EZ-Barbell curls: 4x10
Incline dumbbell curls: 4x8,8,6,6

Triceps:
Pulley pushdowns: 4x12,10,10,8
Lying French press: 4x10,10,8,6
Close grip bench press: 4x10,10,8, 6

Forearms:
Wrist curls: 3x15,15,15

Day 2

Legs:
Squat: 5x15,12,10,8,6
Leg press: 4x12,10,10,8
Leg extensions: 4x12,12,12,10
Leg curls: 4x12,10,8,8

Calves:
Standing calf raises: 4x15,12,10,10
Seated calf raises: 4x15,12,10,10
Donkey calf raise: 4x12,10,10, 8

Waist:
Crunches

Day 3

Back:
Wide grip pull downs to the front: 4x15,12,10,8
T-bar rows or dumbbell rows: 4x10,10,8,8
Superset:
Pulley rows: 4x15,12,10,8
Dumbbell pullover: 4x10,10,9,8
Deadlift: 3x8,6,4

Shoulders:
Upright rows: 4x12,10,8,6
Bent over laterals: 4x12,10,10,8
Barbell shrugs: 3x10,10,8

NOTES

1. Each workout should last no longer than 1 hour.
2. Take no more than 2 minutes rest between sets.
3. Always try for more weight or reps but NEVER sacrificing good form in your exercises.
4. Keep a training journal, this way you can keep track of your gains in strength.
5. When you train don't just try to lift the weight, try to feel how the muscles work as well - this will increase the intensity. Remember bodybuilding is about making the muscle work as hard as possible, not lifting as much weight as possible these are two different things.