It is a well known fact that life coaching is not a regulated profession, and basically anyone can call themselves a coach without attending any training, or having any sort of certification. That being said, while I attended my college coaching program, I witnessed classmates graduate whom I wouldn't let coach my dog. So your first step in hiring a legitimate coach would be to find a coach with skill and coaching know how, and to avoid the frauds and ego maniacs.
How will you know if your coach is competent?
You can't necessarily read the testimonials on their website to determine their level of skill- it is very easy to ask a close friend for a testimonial, which I'm sure would be positive regardless of their progress as a client ( not to mention, in my professional opinion it would be unethical to work with family and close friends to begin with), so don't blindly base your choice on a few website testimonials that could be false. Instead, put your feelers out for people who had great success with a coaching relationship, and trust word of mouth advertising. Once you've found a few candidates based on word of mouth.......
You need to interview a few coaches to find the right fit for you.
Yes, I said interview your candidates! After all, you will be forming an intimate, long term professional relationship with this person, so you need to feel comfortable with them. Most coaches offer a complimentary assessment, so use that time to determine if they will be a good fit for you. Trust your instincts, and give yourself permission to immediately walk away from a coach who you don't feel good around. Ask a lot of questions around the areas you would like to work on; for example, if you are looking to start a small business, your coach better own a successful business. If you're looking to improve your image, your coach better look and dress the part. if you're seeking a coach to help you in the area of romantic relationships, you'd be wise not to choose the coach who has been in a stagnant relationship for 20 years, and is sleeping with her neighbor, and her neighbor's neighbor to spice things up a little...... Unless that's what you're into, of course ;)
Is your coach operating from a place of mental and emotional clarity and well being?
A wise bit of advice I took away from my counseling courses was; every helper/ coach/ therapist should have their own therapist. Why? Because having a good therapist makes you healthy, not crazy. In other words, if your coach is actively seeking to improve their life, and keep their own mental and emotional windshield fog free, they will be better at non judgement, and they will be less apt to project their own desires, fears and insecurities on to you. They will be more self aware.
If your coach gives you advice..... RUN
Lastly, beware the advice giver! The premise of coaching is to empower clients with the ability to weigh options, check in with their feelings and create a problem solving mentality that they will carry forward through life's challenges. The coach who gives you answers and solutions has robbed the client of the greatest gift coaching has to offer; empowerment. You will quickly gain an understanding of your potential coaches skill level if you ask them if they give their clients advice.
Hopefully these tips will help you to chose a coach that is a great fit for you while embarking on the awesome journey that is life coaching.