As a former quilt shop owner, I have 2 suggestions.
The Free Sew day is always profitable. The sewers always buy something and other shoppers are usually inspired by all the creativity. We had it every Wednesday, the quilters brought in potluck, it was a terrific thing and lots of fun!
The second is to organize sewing retreat weekends. Small groups relish the opportunity to sew for long periods...again the same benefits as the first.
Actually- third...be friendly but not pushy. Smiles and enthusiasm go a long way to help your business.