I'm a college student this year and have recently started training for the upcoming football season. The workouts that I have been doing with them don't seem to be enough for me. I have been working out for about 5 years without taking many days off. I have shown improvement in my strength training but not so much in my aerobic/stamina part. I have also been looking on the internet for ways to switch up my workout regimen so my body never has the chance to get use to one. I'm recently weighting in at 217 and would really like to get down to 200. ... I have watched all of your videos but I would also like to know how long I am supposed to them, or until failure. Your help would be tremendous!
Weight loss prescriptions depends entirely on what sort of weight must be shed. Fat is easy to get rid of but reducing muscle mass to hit a target weight is much harder. Since the latter is not the problem for most I'll address the former. Eat less in general. Notice what you eat. Eat fewer carbohydrates. If you have the energy and can pay attention consistently try measuring your intake and conforming to certain dietary rules. Read what you can about The Zone Diet. Learn about The Paleo Diet For Athletes. Check out Intermittent Fasting.
As for training, if you want to put on size, train to failure and eat more. If you want to get more powerful and faster without increasing your size do not train to failure, and don't eat too much. If you want to improve your power-endurance you have to train for it. The longer circuit style efforts we use will be helpful in this regard but they are a dead-end if used exclusively and for too long. Everything works, for a while. But doing all sorts of stuff at random simply to keep your body from getting used to doing one thing at one intensity isn't smart either. Focus, then change, then focus, then change.