Trusting a new detailer is something many people have trouble with. In order to find the right one, you need a good understanding of their expertise and professionalism.
Given that you know that you want a quality, professional service, the FIRST thing you need to do is ask people you know if they have any experience with a good detailer. When people pay the big bucks to get their car professionally detailed, they WILL be honest about the outcome. In the case that you have a referred detailer, call whoever you’re referred to and evaluate their professionalism over the phone.
Secondly, whether you have a referred detailer or not, Google for detailers in your area. Keep a mental note on which detailers and detail companies had above a 4 star rating. Read some reviews posted on their pages and that will help narrow down who to go with.
Lastly, call up the most promising of your finds and determine which of those detailers can suit your personal needs.
The bulk of your research can be done before contacting any detailer, so take your time and feel free to call around for the most professional sounding, best reviewed, and if possible, directly referred detailers. Use other peoples’ good or bad experiences to your advantage!