Three Methods: Diet Cardiovascular Exercise Weight Training. In order to lose weight and build muscle you have to focus on three key elements: diet, cardiovascular exercise, and strength training. It will require hard work and determination, but the results will be worth it!Here are some tips on how you can start getting the body you want.ips. 1  Keep your exercises and your meals fresh. 2  Rest is as important as exercise. 3  Work out with a friend-especially when training with weights. 4  It's always recommended to speak with a physician before drastically altering your diet or doing any strenuous new activities. 5  Don't rest too long between sets.