Word of mouth is a great reference

There are three approaches to basic obedience training for dogs: group classes, private lessons, or board and train programs. A full service pet care facility usually offers all three.
The following is an overview of each:

Group classes are by far the most economical way to get the information you need for training your dog. For a fee, trainers usually offer a set of five to eight classes (an hour each week) during which you are instructed by the trainer on how to train your dog. Group class offers dogs an opportunity to socialize with other dogs if the trainer allows interaction between friendly dogs. An adequate group class for a good trainer is about 10-12 dogs. In group class you share the trainer with your other classmates. If however you need more focused time with a trainer, private lessons may be for you. Tip: Ask to audit a class to watch the training style used. Is the class organized? Are people and dogs having fun?

Private lessons are usually based on an hourly rate and offer one-on-one training with the trainer for the full hour. You can take as many lessons as you can afford and space them out to fit your time and budget. Sometimes trainers can work with you in your home

PCSA is the nonprofit trade association for pet care professionals. Founded in 1977, by a group of concerned individuals within the boarding kennel industry, PCSA now unites almost 3,100 individuals and businesses providing a variety of pet care services throughout the United States and around the globe. PCSA is dedicated to upgrading the pet care industry and educating the public about proper pet care. All PCSA members must affirm their commitment to quality pet care, comply with all applicable laws and ordinances, and subscribe to the PCSA Code of Ethics, which establishes standards of conduct in all aspects of their professional lives.