Teen Business Central interviewed a business owner. basically what he said was key for getting customers to come again is… 

1. good products

2. cleanliness

3. good service

So focus on the things try to improve them as much as you can.  like if you don’t have good products ask customers their complaints and try to improve on them. If you need to work on cleanliness don’t open your business for customers until you area is clean make it your top priority.And if you need to work on good service have a good attitude, help customers as soon as you can, and try and smile.