In different countries, different styles have developed based on differing opinions as to theory and technique. There are over 460 acupuncture points. My ideal is to use the fewest number of needles possible while addressing every aspect of the patient's complaint. I choose points which most precisely treat all your symptoms and their underlying causes. If you are interested in furthering your understanding of Acupuncture theory, flip through some of the books at the library in my office, ask me your questions during treatment.
Training varies from no time to three years.
I attended a four year school. MD's may insert needles with no formal acupuncture training. I would first consider whether I thought the acupuncturist exemplifies well being. I would make note of how easy it is for me to communicate with them. You could also ask about where the practitioner trained, how long the training was, how long he or she has been in practice, if he or she is licensed, and what experience the practitioner has had in treating your specific ailment.