By looking at the demographic and psychogenic markup of your current customers, you can find out other things that a large part of them are in-market for. Things that interest them or they are looking to buy.
You find such an interest area that does not contradict your brand, and find good partners in that field. Invite these partner(s) to do an event with you at your store.
Your customers will appreciate it (the large group that is interested.) The partner will like the new business and clients they get. And you’ll get a commission on sales from the partner.