Before beginning any exercise program, you should see your health care provider for a physical and medical clearance. If you are using a personal trainer, be sure that the personal trainer you choose puts you through a comprehensive assessment to evaluate medical history, personal goals and look at your current physical status.
If you are not using a personal trainer, always begin and progress slowly. Begin with light weight, higher repetitions at a slow and controlled tempo at first. This will help prepare your body for the stress of strength training and correct poor movement patterns. Stay at this lower level of intensity for 4-6 weeks as this will allow for optimal adaptation time. After this you can begin increasing the intensity and durations of the workouts.
Vary workouts to include both cardiovascular and weight training. Some days can be more focused on weight training while others can be focused on cardiovascular training. Make the exercise fun, but working out with a friend. Several studies show that social support greatly improves workout participation rate.