Most main branches of complementary or alternative medicine have a regulatory body or a college to which a practitioner may be affiliated. Some are more officious than others but all demand a basic standard of technique and stipulate a certain amount of time spent in training to be able to join.
Unfortunately, many healing arts do not have any form of association and there is currently no legal requirement to have studied the subject that a practitioner may claim to practise. I believe that this will change in the near future. For now, however, the best method of choosing a practitioner is through word of mouth. Qualifications do not necessarily ensure that a practitioner has healing qualities but if they have helped someone they are likely to be able to help others.
If you cannot find somebody in this manner, then select a practitioner from a reputable clinic. It is unlikely that a practitioner who is not safe or effective will flourish within a group. Other practitioners will hear any detrimental information and either correct the failing or recommend to the clinic owners that the practitioner is not suitable.
A waiting list is usually a good sign. You need to ask how many days a week that an individual may work with patients. I know of a practitioner who has a remarkable reputation based on a six-month waiting list. He only works one day a week! Most practitioners should expect a six-day waiting list!
Good practitioners are busy practitioners who, as a rule, do not need to advertise. Accepting that everybody has to start somewhere and that advertising is a method getting one’s presence known, an advert may represent an unexperienced or failing practitioner. An advertisement may be drawing your attention to a new field of practice or a unique technique but selecting a practitioner by this method may not be the best. It is better to go on articles that you may read, because journalists are generally quite scrupulous and have experience. Always, however, look for the political motive in anything that is being written about complementary medicine. I may be overzealous in my belief that the orthodox world would not like to see complementary medicine flourish but I do feel that many articles on the subject are overcritical and do not compare the down side of orthodox medicine when criticizing an alternative technique.
At the end of the day you need to be comfortable with your chosen practitioner. If the area in which they work, the room in which they practise or their character feels uncomfortable then look again. Trust your instincts.