For many people formulating a fitness plan and sticking with it can be tough. They need a personal trainer to show them the way. But not all trainers are created equal. Finding the right match for you can take a little research, and a little time.

First things first—money. Some fitness centers have trainers on staff and others are independent contractors. Most trainers will usually run you anywhere from $40 an hour to more than $150 an hour, depending on where you live.

To find a trainer who's right for you, start by asking friends—or poking around at your gym for referrals. Don't be afraid to ask questions.

Check that they're certified from an accredited organization. There are more than 400 certification programs out there. Among the most respected are the American College of Sports Medicine, the National Strength and Conditioning Association, and the American Council on Exercise. A degree in physical education or exercise science is definitely a bonus. And experience matters—so don't be afraid to ask to see a resume.

If you go with an independent contractor, make sure they have professional liability insurance in case you get injured.

As you interview personal trainers it's important to keep your eyes and an ear out for someone who listens carefully. What matters most are your goals and limitations, not theirs. So it's important that they listen to your needs. And beware of people trying to sell you things like dietary supplements.

Details need to be covered, too. Will they meet at your home or at a gym? How will they track your progress? What is their cancellation policy? If you have any medical conditions, try to find someone who has education in that area and will consult with your doctor.

Finally, personality is important. Remember you're going to be spending a few hours a week with this person and it won't always be pretty. You've got to enjoy their company and look forward to your sessions.