The first thing to look for when selecting a hypnotist is to see whether they have been certified by one of the two major governing organizations of hypnotists. One of those is the National Guild of Hypnotists (NGH) and the other is the American Council of Hypnotist Examiners (ACHE).
The next thing you might want to consider is if the hypnotist is Board Certified. Board certification means that the hypnotist has practiced for at least a year and has passed written and verbal examinations.
Then, another consideration is the level of experience of the hypnotist. Sometimes we just want to see the practitioner who is most geographically convenient or the one who has a deal on Groupon, but when we are talking about major life changes, it makes sense to choose someone has experience working with the issue you want to address.
So, call a few hypnotists and talk to them. Go to the one who understands your situation and the one who you feel has the best chance of helping you succeed.