Start slow. Don't overexert yourself in the gym by ramping up the speed on the treadmill or adding a lot of weight to the bench press to try and impress anyone. You'll increase your risk of injury and exhaust yourself unnecessarily.

A good way to find your weight range (the amount of weight you can safely lift) is through a trial of four sets. For each set, you should add a little more weight (5-20 lbs depending on the starting weight) to the bar or machine and perform a fewer repetitions of the exercise. The first set should be 15 reps; the second set, 12 reps; the third, 10; and the fourth, eight. The last set should be the hardest and require near-maximal effort.

If you don't know how to operate a certain machine or perform a certain exercise, ask a trainer. Many gyms also have weight room supervisors that are there for the sole purpose of answering clients' exercise questions. Also, many gyms offer a free-trial personal training session, so take advantage of it.

Before you start your workout regimen, perform this simple test to accurately gauge your fitness level:

Do as many pushups as you can. You can perform modified pushups (on your knees) if needed.
Do as many squats as you can while maintaining proper form.
Get on the treadmill and run at a 5-6 mph pace as long as you can.

Record these numbers in your fitness journal so you can track your improvement from week to week.

If you're just starting out, it's important to set goals for yourself to keep you motivated. Don't make the common mistake of setting your goals too high, though. Once you've completed the fitness test described in step four, you will have a better idea of what you're capable of. So based on your results, set reasonable, moderate goals.

Bring a water bottle to the gym with you when you work out so that you can avoid becoming dehydrated. As you sweat, you're losing water and electrolytes, so aim for 7-10 oz. of water every 20 minutes. If you're exercising for more than 45 minutes, try a sports drink like Gatorade. There are even low-calorie/sugar-free ones available if you're trying to lose weight.c