I have a friend who has made hundreds of quilts but will sign up for a class anytime she sees something interesting and challenging. If I am around her, I sign up too, even though most of the time, I could do it on my on. It's the friendship, comraderie thing. If it is a small item, she will finish it in class. It takes me much longer. I'm like the lady who wishes there was a follow-up class to remind me what I need to finish doing.
Some thoughts....
Maybe 1 price for 1 person with a discount if they sign up a friend. 5 friends come, you get a free class. Groups are much more fun.
I like it when the shop offers a 10% discount on anything we buy on class day or for the project.
Definitely find out what people want to learn how to do. A friend of mine just taught Night & Day by Eleanor Burns and had 10 people sign up. Surprised the heck out of her. Another purse class she did had more sign up than she anticipated.
I find I want to learn something new that I can't figure out on my own, or wouldn't try on my own.