Never ask a client to do something that you wouldn't do yourself. If you tell a person to drop and do 1000 burpees, you best have done that within the last 72 hours and if not then get ready to drop and do it with them!
An exercise training program must continually build, constantly offering the body and muscles new challenges so as not to plateau, and to continue to rev up the metabolism and build stamina. But how that is done is truly relative and specific to each client.
Starting a new health and fitness regime, changing careers or simply dealing with the challenges thrown up in day-to-day life can be daunting and intimidating. Learning to coach yourself through situations like this is possible.
Keeping your body healthy and well nourished with healthy food choices will keep your metabolism working most efficiently. Combine this with a calorie deficit and watch your fat cells shrink. It all works together!