Advertise low priced transfers. So many gun shops want to charge a arm and leg for them to receive a gun for you, I give my business to those that don't.
If applicable in your state, get a CHL instructor that has a flexible schedule. One that can work off hours to meet the customers needs. If applicable in your state, offer Hunter education classes.
Do they have a range? If so run ladies nights, Appleseed shoots, vendor days, etc.
Vendor days and special days for ladies are nice. One LGS here had a day where vendors that specialize in shooting gear for women were the focus.
Talk to the local chapter of Friends of the NRA about handling their banquet guns.
Offer on site build help for AR owners. Got a local shop that specializes in ARs, they don't have a FFL just parts, lots of parts. The thing they do have is a work bench where the owner helps you assemble parts on your gun prior to purchase. He has all the tools, knowledge, space etc. to cater to this.
.