Figure out how to pay the bills. Bodybuilders don't make lots of money, so the idea of becoming a professional bodybuilder is a lot like the idea of become a professional poet or professional painter: it'll take a lot of your heart and soul, but you'll also need to figure out how to take care of the practical details. You've got to support your bodybuilding with some other kind of work to pay the bills.

Rest and recovery: Remember that muscles grow during downtime, not when you train, so allow a day or two between workouts when you first get started so that the muscles can recover and grow. You should show up at your workouts refreshed and at least as strong as the previous workout (there will be days when you aren't stronger, and you should expect them so don't get discouraged when it happens).
If you have little experience of weight training and free weights, you may wish to start with the machine leg press instead of the squat, especially if you're not accompanied by a trainer, helper or spotter. Even so, there is no reason to be intimidated by the squat exercise. It need not be done in a squat rack or power cage with the big bar and free weights to begin with, although squatting with the bar alone is a good way to practice form. Dumbbells or small-bar barbells or a Smith machine can provide reassurance for the beginner. The same applies to the racked bench press with heavy bar, which can be substituted with dumbbells or lighter barbells. The key is not to lift too heavy too soon.
Milo of Croton, the ancient Greek athlete, strong man, and wrestler, may be credited as the first athlete to use the principle of progressive overload. Legend has it that Milo trained for the Olympics by carrying a newborn calf on his back every day for years prior to the Olympic start date, and by the time the Olympics arrived, the calf had grown to a full-size cow, and Milo was still carrying it on his back! In essence, Milo adapted to the growing weight of the animal by growing stronger himself. That's progressive overload. To follow this model for developing strength and tone, you lift weights that are heavy enough to create muscular fatigue at the 10th to 12th repetition and then when that gets easy, you increase the weight and lift that new weight until you can do it again for 10-12 reps. You can increase the weight every time you get to 10 or 12 reps. Typically every time you add new weight, you lift fewer reps because it's heavier, but then as your muscles grow stronger, you perform more reps.
Muscle growth is more difficult to achieve in older adults than younger adults because of biological aging, which leads to many metabolic changes detrimental to muscle growth; for instance, by diminishing growth hormone and testosterone levels. Some recent clinical studies have shown that low-dose HGH treatment for adults with HGH deficiency changes the body composition by increasing muscle mass, decreasing fat mass, increasing bone density and muscle strength, improves cardiovascular parameters, and affects the quality of life without significant side effects.[45][46][unreliable medical source?][47]

After a tough sweat, it's important to rehydrate your body: "Drink lots of water and thank your body for what it was just able to accomplish," says Davis. A balanced post-workout snack is also a good idea. Go for one with carbs refuel your glycogen stores (one of your body's main energy sources) and about 10 to 20 grams of protein to help build and repair your muscles. "Don’t overcomplicate it," says Davis. If you're lifting and weight loss is one of your goals, though, it's still important to keep calories in mind—a post-workout snack shouldn't be more than 150 to 200 calories. Here's a guide to how many calories you should be eating for weight loss.
Before hitting the sack, snack on a combination of slow-digesting casein protein and healthy fat. Casein coagulates in the gut, ensuring a steady supply of amino acids to slow catabolism as you sleep. About 30 minutes before bedtime, have 20–40g of casein protein powder or one cup of unsweetened low-fat cottage cheese (a stellar casein source) mixed with two tablespoons of flaxseed oil or one to two ounces of nuts or seeds.
Overeat. Increase your daily intake of energy (calories) by about 15 percent. It should not be all protein but the extra protein you consume, either in supplements or protein foods, should be low in fat. Stay close to the current guidelines for protein requirements for weight trainers. Hiring a sports dietitian with some experience in weight training is also an option.
If you've been competing for five-plus years, there is a quiet confidence that comes from knowing what you bring to the table. If it's your first time, don’t allow yourself to get rattled. Nerves cause cortisol to shoot up, which causes water retention and all kinds of other unwanted issues. If you’re well prepared and you have done all the hard work, it's time to enjoy the fruit of your labor.
Be patient! Too many people want it all right now so they become frustrated if they haven’t built their dream body within a few months of training. When such a point is reached, many bodybuilders either quit altogether, or turn to dangerous drugs such as steroids, or synthetic hormones in order to speed up the process. Steroids are insidious. They may produce rapid gains in the short term, however, the compromises are extraordinary and should be very carefully considered. The steroid users that I knew 15 years ago that I wished I could look like are now either dead or out of shape dealing with severe health problems. If you love bodybuilding like I do, then you will want to be able to do it, and enjoy it from now until well into your golden years of life. Don’t get discouraged when progress doesn’t seem to be coming quickly enough. I’ve been there before, so I know how it feels. I can tell you from experience that if you are persistent it will pay off eventually. It took me 26 years to put on 40 lbs of muscle! That averages out to roughly 1.5 pounds of muscle gained each year!

When you combine cardio, weight training, and diet it's a triple threat that can't be ignored. When doing cardio it is extremely important to determine your maximum heart rate (220-age) and then to determine your heart rate zones which is usually 60-90%. (For example a 20 year old: 220-20=200. 200x0.60=120 & 200x0.90=180. Thus, their optimal training range would be 120BPM - 180BPM)
Of all the macronutrients, protein is most important for cutting. While it will be carbs you miss the most, when cutting down calories, protein is important to build muscle which boosts your metabolism. Therefore, you’ll need to keep up your protein intake. Products such as Whey Protein Concentrate (WPC) allows you to consume a greater intake of protein without overdoing the calories, they are also available in tasty flavours than can curb any sweet cravings too.

Shorter rest periods have their place — especially if your goal is muscular endurance and fat loss. But longer rest allows you to perform more reps on subsequent sets, and this greater volume, over time, may lead to greater muscle gains in the long run. One convenient way to do this without tacking additional time onto your bodybuilding routine: Perform supersets, which are back-to-back sets of two different exercises that target non-competing muscle groups (e.g., the squat and biceps curl, or the bench press and bent over row).

Arnold wrote that he always included at least one dumbbell movement in his routine. By supinating his hand (turning it upward as he curled), he felt he got a greater "peaking" effect because the brachialis is recruited into the motion when the hand starts in the neutral position. Arnold performed supinating dumbbell curls simultaneously and with alternating reps. The latter allows more body English and a bit of rest between reps.
The bulk of the workout should consist of basic compound lifts, like the traditional barbell squat for quads. If you stop progressing in strength gains on leg exercises, you are most likely overtraining. In that case, give yourself more time between the leg days and cut back on the volume. Also, to speed up recovery, always stretch before and after your workouts.
I will do a video on deadlifts soon. It’s funny you mention that because most people have the opposite issue, their back takes over for weak legs and they aren’t sitting in the position low enough to begin with. You sound like you have great leg strength but your back isn’t engaging enough. You may want to try pre-exhausting your back first with a few high rep sets of hyper-extensions w/ just bodyweight, THEN go to deadlifts
In either phase, don’t exceed 1 gram per pound of body weight of protein (2.2 grams/kilogram). A little more probably won’t hurt a healthy person, but chances are, based on the science of protein requirements for athletes, it won’t help either. It will only cost you in expensive supplements or food. Any hint of kidney disease and you would need to be cautious about excessive protein intake. Consult your doctor for advice if this applies.