What is the most important part of an exercise program?

Enjoy your exercise: It does not have to be trendy! good old walking is simple and inexpensive. Be as brisk as you can for 30 to 45 minutes. Any other aerobic activity you enjoy such as biking, dancing, swimming, climbing are also good. Also toning and building your muscle with lighter weights (so that you can comfortably do more reps) increases your metabolism, helps weight loss and is heart healthy.

Several things.: Consistency, good technique (consider a trainer), recovery, cross training (vary your activities), finding activities you enjoy that you will stick with, healthy diet, setting goals, being realistic, having fun (recruit a trading partner).