I started working with a personal trainer about two years ago...a couple of questions I asked and that he asked?
(1) Are you certified? What are your credentials? How long have you been doing this? Can you give me some of your referral clients that I can call?
(2) What is your cancellation policy, if for some reason I can not make it to the session, will I be charged? Instead of paying per session, can I pay a monthly fee for X amounts of session per week (you can compare which is better sometimes they do have a discount if you go monthly versus paying for the session)
(3) What are your goals Kd? He should be asking...this question back to you...are you trying to gain size, loose weight?
(4) He should also be asking...what has been you level of activity?
(5) There should be a pre-workout session to take in your measurements, etc. a baseline to draw upon the next weeks to compare to.
(6) They should also be talking to you about nutrition, what are you eating, etc. and they will be asking you to complete sort of a diary log to see what you are consuming. Then you will bring it back and they should plan sort of a plan for you based on your goals.
(7) When training with the trainer, ensure that he understands what you are comfortable or not with the exercise, if you have any medical condition, i.e back problems, etc...the trainer should be knowledgeable enough to do another exercise to achieve the desired exercise without injuring that section of your body that you might be having difficulty in performing.
A good trainer shows you the proper form of performing the exercise, the really good ones will do a few reps and watch your form, the poor one will not. The good trainer will constantly give you feedback and stop you when you are not doing the correct form...at this stage it is better to ensure that you are doing the exercise properly.
(9) Also, if you like one trainer try to stick to him, is difficult when they switch trainer on you. Also, a good trainer should be able to push you.
These are some suggestions that have helped me - good luck.