Whether you're learning to move your body after a long period of couch potatohood or trying to take your already-advanced fitness routine to an elite level, a personal trainer can be instrumental in helping you reach your goals—and not just because he'll poke you in the ribs and demand ten more reps when you start to slack on your workouts.

A certified fitness professional can teach you everything from good nutrition to proper lifting form, and the best ones will give you knowledgeable guidance and support every step of the way (not to mention a serious financial incentive not to let your gym membership go unused). But as with any service provider who's getting up close and personal with your body—and your psyche—it's key to get off on the right foot and make sure the working relationship will be a good one. Here are a few tips from the pros on how to have that first conversation.

1. YOUR TRAINER SHOULD ASK YOU ABOUT YOUR LIFE; YOU SHOULD ALSO ASK ABOUT THEIRS.

It's good to have certain things in common with your trainer, and not just because it'll give you something to chat about between squat sets. Lifehacker writer and personal trainer Dick Talens suggests finding a trainer "who has many of the same characteristics as you"—someone whom you can look to as a realistic source of inspiration, and someone who will understand and empathize with the path you're currently on.

For example: If you're starting from absolute zero and have never lifted anything heavier than a cat in your life, the trainer who's been an elite athlete since birth probably isn't the best fit for you. If you have kids and a cramped schedule, look for someone who's been there, too. And if you're bringing a lifetime of emotional baggage surrounding food and fitness to the table, a trainer who's struggled with the same issues—or who trains a lot of people who do—is your best bet for making sure you get as much support as you do motivation.

2. BE REAL—AND REALISTIC—ABOUT YOUR GOALS.

You'll get the most out of your training—and your trainer will be best able to help you—if you're working toward a specific, achievable outcome, whether it's performance-related (doing a pull-up) or appearance-related (getting that coveted six-pack.)

"You want a client to have a specific goal in mind, and you want to be sure that goal is reasonable," says Ray Gregory, a freelance NASM-certified trainer from Princeton, New Jersey. "Most people want to look good for an ex/wedding/event in an unreasonable amount of time."

You and your trainer should discuss what you're hoping to get out of your time together; he should also be honest with you if what you're asking for is unrealistic or not in his wheelhouse. "Health and fitness is a broad field, with goals ranging from sport specific performance, to aesthetics, to general health and fitness. Many of these don’t necessarily overlap," Jonathan Mielec, CFT, of Form From Function Fitness explains.

If he lacks the expertise to get you where you want to go, or if your goal isn't reasonable (e.g. Halloween is next week and you want Hugh Jackman's bod to go with your Wolverine costume), a conscientious trainer will help you revise your expectations and settle on some achievable benchmarks that fit within your lifestyle and your timeframe. Or, in the case of sport-specific goals, he'll refer you to someone with the right credentials.

3. REMEMBER THAT A TRAINER IS NOT A MAGICIAN—AND DON'T TRUST THE ONES WHO CLAIM TO BE.

"Be wary of unrealistic expectations on your part or unreasonable guarantees on the trainer's part," says Mielec.

Being a salesman is part of a trainer's job, but the good ones won't resort to false advertising or empty promises. Be particularly wary of trainers who make wildly generalized claims ("I can whip anyone into shape in six weeks!"), who push you to buy add-ons like accessories or supplements, or who make the whole process sound too good and too easy to be true.

The professional you want to work with is the one who's honest with you about how much time and work it'll take to get the results you want, because he wants to see that happen just as much as you do. "It hurts the trainer just as much when your client doesn't meet their goals," Gregory says.

4. TALK ABOUT YOUR PAIN.

Any initial meeting with a trainer should include a discussion of your limitations, especially injuries. All fitness professionals have some degree of education in anatomical health, but depending on the nature and extent of your injuries, you may be better off with a trainer who's specifically knowledgeable about therapeutic exercise.

"Always be open and honest about any injuries and/or conditions you might have," says Mielec. "You should hear that the trainer is prepared, experienced, and educated to work around or work on those issues."

5. IN A FITNESS RUT? ASK ABOUT A TRAINER'S SPECIAL INTERESTS, AND PICK THE ONE WHO'S STRONG IN AN AREA WHERE YOU'RE ENTIRELY CLUELESS.

When exercising is already a regular part of your lifestyle, finding new ways to challenge yourself can be the thing that takes you to the next level. And if you're looking to work with a new trainer, this is the time to choose one who will push you out of your comfort zone.

"If you know your way around the gym, find a trainer who will challenge you," says Gregory. That might mean signing on for a few sessions with the scary bootcamp-style trainer whose coaching approach was too intimidating for you when you first started working out; it might also mean exploring types of exercise you've never tried before. Every fitness professional has areas of special knowledge, whether it's gymnastics, power lifting, competitive bodybuilding, or working out in preparation for the zombie apocalypse, and tapping into that can really rejuvenate a boring workout routine.