(CNN) -- When he watches personal trainers work with their clients at the gym he uses, Marqus Taylor often isn't impressed.
"From what I've seen, personal trainers tend to get in your face and make you feel less than you are," he says.
Taylor, 30, is grateful he met his trainer at a local church in Chicago -- Brian Harris is full of kind words and encouragement, which has helped Taylor lose 160 pounds.
Finding a personal trainer who makes you feel comfortable enough to expose your biggest flaws can be challenging. But they're called "personal" trainers for a reason -- they're there to guide you to your personal fitness goals, and to do so, they need to fit with your personality.
The number of personal trainers in America will jump 24% by 2020, according to the U.S Bureau of Labor Statistics. As the field increases, clients will need to do more research to find the perfect fitness coach. It's important to consider everything from what your trainer wears to how they talk.
Here are five qualities you should look for in a personal trainer:
Patience is the key to a good client-trainer relationship, says celebrity trainer Ashley Borden. Trainers should understand that what works for one client may not work for another. He or she should do an assessment of your body when you first meet to familiarize themselves with your needs.
Trainers should also find a comfortable pace for their clients, Borden says. Some clients may progress at a faster rate, while others may require more coaching and assistance.
"I love teaching and the journey of helping people find their bodies again," she says.
Your trainer likely will not be with you at all times during your workouts. That said, they should be able to explain things to you on the phone and teach you how to do certain moves without physically being present through every workout.
"(Harris) went above and beyond," says Taylor. "When I first started the new plan, we spent half the day at the grocery store buying healthy foods because I'm not a smart shopper."
Taylor says since Harris told him what to eat and why, he has been able to shop and work out on his own.
And communication goes two ways.
"If a client always cancels on me and pushes back workouts, it makes me feel like they aren't committed," Harris says.
While it's important to maintain a close relationship with a client, Borden says, there also needs to be a level of professionalism.
"I carry their water and get them a towel if they need one -- similar to service they would receive at a five-star hotel," she says.
(That service comes at a price: Full-time trainers charge an average hourly rate of $28.27, according to the National Federation of Professional Trainers. The duration of your training session, the location and the experience level of your personal trainer will dictate the cost of your session.)
Lastly, the clothes your trainer wears should be simple and plain. The attention should be on the client, Borden says -- not on what the trainer is wearing... or not wearing.
Trainers should have -- and be able to show you -- an appropriate fitness certification for their area of expertise, Borden says.
To become certified, personal trainers must pass an exam through accredited organizations such as The American Council on Exercise (ACE), the National Academy of Sports Medicine (NASM) or the National Strength and Conditioning Association (NSCA).
Most exams cover exercise physiology, training and exercise procedures, nutrition, functional anatomy of the body and weight management. Each organization's certification exam will ask different questions. You can see an exam overview here.
A high school diploma or GED is necessary to enroll in certification classes; however, not all employers require college degrees -- this will depend on whether your trainer practices privately or through an institution.
Trainers should also stay up-to-date with the latest fitness trends and new research published in scientific journals.
"Basic fitness is always there, but this field is evolving," says Borden. "I always check online to see if there are new studies or courses I need to look at."
As a client, you want to feel comfortable and trust that your trainer has your best interest in mind.
"Brian is like my brother," Taylor says. "We are really close in and outside of our training because he talks to me like a real person, not like a customer."
Once you have established what kind of personal trainer you want, you can start looking for them.
The American Council on Exercise and IDEA, the world's largest association for fitness and wellness professionals, have online tools that can help you locate the personal trainers available in your area and filter your results to cater to your activity of interest, price range and gender.