1. DO have fun! The benefits to working out don't pay off if you don't enjoy yourself. This isn't an excuse for not exercising, as it's still vital to your health. But finding a workout that you enjoy will make the difference when setting a workout schedule that will stick.

2. DO start off moderately.  Work your way into a routine. Going overboard may result in injury, or at least disappointment. Your workout shouldn't do either, so build up from a moderate beginning.

3. DO warm up and cool down.  A low-impact warm-up before any exercise is essential. It warms the muscles, makes them more limber and easier to stretch, which results in a better workout. It also helps to prevent injury.  Cooling down after exercising is also important as it relaxes the muscles, lowers the heart rate, and helps the body to recover from the stress of a workout. It'll make you feel better immediately after the workout, and the next morning.

4. DO stretch.  Flexibility is one of the most important factors of fitness.  Stretching before, during and after a workout will result in better performance, good posture, fewer injuries, and overall better fitness.  Be sure to warm up before doing any type of stretching.

5. DO be aware of the muscle you are trying to work.  Each exercise described is designed to work a specific muscle group or groups.  If you are not feeling that muscle group, you may be doing the exercise incorrectly.

6. DO hold your abdominal muscles tight while you are doing any exercise.  It is important to protect you back while you are strength training.  Contracting your abdominals while you are completing the exercises will help do this.  To practice contracting your abdominals, pretend someone is coming at you and they are going to try to punch you in the stomach.  Your flinching reaction to protect yourself is most likely your abdominals contracting.  It is important to distinguish between sucking in your stomach and contracting your abdominals.

7. DO watch what you eat.  Diet is just as much a part of fitness as exercise, and what you eat will affect every aspect of your workout. A proper diet also influences the results of you fitness plan, since it helps build muscle and decrease the percentage of fat in your overall body weight.

8. DON'T hold your breath while strength training.  Holding your breath while strength training may cause an increase in blood pressure and a headache.  You should exhale on the exertion.  This means you should be blowing out while you are working against the resistance of the cylinders.  For example, while doing the leg extension you should be exhaling while you are extending your knees.

9. DON'T dehydrate yourself.  When exercising, the body needs four to eight ounces of water every 20 minutes to replace water loss. If you become thirsty during a workout, you've already passed out of a "safe" stage of hydration. Take fluids immediately. Always avoid caffeine or alcohol when exercising, both of which further dehydrate your body.

10. DON'T lose concentration.  Preoccupation with outside situations can counteract the benefits of a workout. For example, you might decrease intensity as you lose concentration. And not paying attention to a workout can lead to sloppy style and potential injury. Instead, use the time to concentrate on proper form and control. It will lead to a better workout, greater benefits, and a more relaxing experience.

11. DON'T continue to do an exercise if you cannot maintain proper form.  Being unable to maintain proper form means your body is getting tired.  You increase your risk for injury if you continue to do an exercise in this manner.

12. DON'T over-exercise.  For maximum benefit at minimum injury risk, the body needs to rest and recover. At least a 24-hour rest after heavy muscle strain is advised. Stagger workouts between heavy and light strain. For example, you can alternate the 30X3 workout with biking. 

13. DON'T push an injury.  Listen to your body. If you feel pain, stop. Muscle and joint pain can mean many things -- pushing a small hurt can lead to big problems later on.