Here are links to local indoor tennis clubs where you can sign up for group lessons. Most of these do not require a membership to sign up for group lessons. 8 week lessons should start mid-January. You can always get a group together and do a small group private lesson.
Lifetime Rochester Hills (Avon and Rochester)
Troy Racket Club (16 and Livernois) This location has holiday short sessions also between Christmas and New Year. They can tell you what class to take and will move you based on your skill level. I play here and the coaches are good.
Birmingham Racket Club (Coolidge between 14 and 15) They have a beginner program that starts with enough interest
Franklin Athletic Club - (Northwestern Highway north of 12 mile)
Wessen Indoor Tennis Club - (Pontiac - near Orchard Lake and I75) - good drop in programs for nonmembers
Size - larger racket head size has a larger sweet spot (100 to 107 square inches)
Weight - lightweight is better to prevent arm fatigue and help to improve form (9-10 ounces)
Grip Size - you should be able to grip your racket easily with a small space between your fingertips and the palm. Sizes range from 0(4⅛ in) to 4 (4½ in). 2 is a good place to start for most people, but err on the smaller side as grip tape can be added.
Good Article about choosing a racket and different aspects of rackets: CLICK HERE Do not get a children's racket or junior racket unless you are a small person as they are smaller and have very small grip sizes.