It is important that you have a proper plan in place when it comes to rewarding individuals. Decide on a particular behaviour which you want to encourage and how you will be able to do that in a limited budget.
Remember, the return on investment may be your prime intention but that must not come at the expense of exploiting your customers through misleading deals and promotions. You must decide on the target audience and how frequently they visit your store. Keeping them satisfied is your main goal and the reward program is a way to encourage positive behavior. However, you cannot cover everything under one program so decide on a particular conduct and try to improve or manage it within a certain budget and time frame.
The most important element of the reward program is the reward itself. You can use either use a tier structure, depending on the target audience or the amount they have spent, or simply cater to a wide consumer base. For instance, discounts are a common way of luring customers but you should go beyond that by rewarding your regular consumers with a points system, free gifts such as mugs, buy and get one free offers and movie tickets etc.
Make sure that you keep it simple or set a time frame for the whole program, during which you communicate with your customers on how to improve the system. If you feel that the program is off your budget, then look at non-monetary factors, such as knowing the names of the regular customers by heart. This may be the best way of keeping them loyal.
Keep track of the program from the day of announcement to the finish when the rewards have been handed out. You can announce the results if possible in order to promote transparency. Create a feedback process as well, which allows you to fill any holes in your program.