1. The power of related products
A very important feature of a good point of sale system is the ability to specify items/product related to another product. For example if you sell the hamurger the fries and the coke are related items and the POS system should prompt your staff to mention this to the customer.
2. A customer display screen
This is an additional LCD monitor that faces towards your customers and display special offers and reminders in relation to product. This can be such things as buy 2 cans of soft drink for $x dollars and other deals that rotate in front of the customer. During the sale the point of sale shows the customer the items they are purchasing and the total, but either on the side or the bottom the customer display screen shows offers.
The above 2 features alone can take you a long way to boosting sales by 10 or 20% with minimal effort.
For more information on a point of sale system with these features check out PBSA POS
