The best tattoo artist should be a fully licensed professional and if they are not, there is no guarantee that their studio and equipment will be clean. Cleanliness is a necessary factor when choosing a tattoo parlor because diseases are spread and infections are caused very easily if the equipment is not sterilized properly.
The most experienced and professional tattoo artists will help guide you if you are having some doubts on the outcome of your tattoo design also a good tattoo artist will never push ideas on to you, they should give advice only.