Keep aware of what's happening in your area, then promote and sign your store accordingly. Be specific in your ad, flyer and sign copy. Make your pricing easy to understand on signs. Do the math for people. Help your customer buy the best product by signing similar items with an increasing number of features.
Customers can see that for themselves.
Sign beyond your advertising. Customers often trade themselves up to better, higher margin items. Signs are for your employees, too. Use them to inform and motivate. Promote and sign every one of your services.