Growth gains:
Calories are one of the keys to getting big. Without sufficient calories the muscles will not grow. Try to consume anywhere from 20-25 calories per pound of body weight per day to gain mass. About 18 calories/lb of body weight/day to maintain. Less than 18 cal/lb/day to lose weight. Weight gains and loses of more than 2 lbs/week are not desirable. This means you will either gain too much fat when gaining weight or lose too much muscle when losing weight. Protein is probably best kept at 1g per pound of body weight. So for a 200 lb weight lifter that would be about 200 grams of protein. It is a real good idea to eat high protein meals at breakfast and dinner and higher carb meals at lunch. Also try to take in from 20-50 g of protein within 2 hours after you train. I would strongly suggest that you consume about 55%-60% of your daily calories from a carbohydrate source, 15% protein, and 25%-30% fat. The last week before competition, back off the carbohydrates (40%) and increase the protein (30%) and fat (30%).
Aerobic training:
Of course the more aerobics you do the more calories you will burn. If you are trying to gain mass or strength it might be a good idea to cut back on or cut out the aerobics. When losing weight or cutting fat, the aerobics can be done daily. Remember to keep track of the weight loses. More than 2 lbs per week may mean you are losing some of that hard earned muscle.
Rest:
Sleep is very important. Try to get about 8-9 hours of sleep per day. About every 6-10 weeks take about 1 week away from the gym and do what is called active rest. This active rest should be any thing but lifting weights. Active rest will give the body a chance to recover from all of the stress and prevent overtraining.