How to find a suitable coach 

Finding the right support for issues you are dealing with can be tiresome. At present, getting a psychotherapy place is like winning the lottery. Many who want competent support are therefore also reaching out in the direction of coaching. For Berlin alone, internet search engines show x-thousands of hits for coaches. So availability doesn't seem to be a problem here. But how do I find the support that suits me and my issues and actually helps me? 
First of all, an important fact to start with: coaching is not a legally protected term. This means that no training is required to offer coaching. Basically, any person who is interested in accompanying people on a development path can do so under the title of coaching.
If you have a specific topic, project or problem that you would like to be supported with, you can, for example, see if there are coaches who have gained experience in this area and/or specialise in it.
The fact that there is no need for training to become a coach does not mean that there is no such thing. There are various training formats that differ in terms of orientation, methods, duration, etc. You can read about your coach's training on their website or ask directly how your coach qualified and which method/orientation is the main focus of their coaching. The same applies to membership in umbrella organisations.
As with finding a therapist, I recommend that you take your time to find someone with whom you feel comfortable and safe. In the best case, coaching offers you a trusting setting in which you can look at, navigate and develop your issues.  This works particularly well if you like your coach and have trust in their competence and guidance. An important point that shows the quality of the coaching relationship is, for example, how your coach deals with conflicts between the two of you.
You can also ask acquaintances if they can recommend someone to you. A professional coach is bound by confidentiality and will keep your processes and issues strictly separate. However, I would advise against visiting the same coach in love relationships (more on this at another point).
You have found someone with whom you can work successfully and trustingly? Wonderful!
It may be that you realise that certain issues are perfectly suited to this setting, but that you perceive that you are not making progress together on other issues. This does not necessarily mean that you have to end the coaching relationship. Perhaps it is simply a matter of splitting the topics. Have the courage to bring this up with your coach! They may even have a recommendation for you on who might be suitable to accompany the "dead-end issue". 
Last but not least, a platitude: people change. Coaching is exactly a means to that end. So it may well be that at some point you feel that things come to an end with this coach (or coaching at all). A competent and well-intentioned coach is interested in you being independently satisfied with your life and following the path that is right for you. A farewell conversation can provide the space for a shared appreciation of the coaching process and keep the door open to meet again in the future or ask for competent colleagues.
I wish you all the best in your search and that you find a coach who suits you and does you good!