The more a shopper interacts with staff during their visit to a store, the greater the average sale will be, according to research, so it's important to start off a customer's visit the right way.

Allowing shoppers to enter the store without being greeted can make them feel invisible. But an overzealous sales person who pounces the second someone's foot crosses the threshold with a loud "Can I help you?" or an overly emphatic "Welcome" can be overwhelming.

First, employees need to be aware whenever someone enters the store. Staff should be trained to watch the store entrance like a driver uses a car's mirrors. They don't have to stare at the door constantly, but they should get in the habit of glancing at the entrance without thinking. It should become second nature.

When a staff member sees someone walk in, they can acknowledge the customer in a number of ways. To determine the appropriate greeting, they should use a system called "mirroring." This is assessing a customer's demeanor and attitude, and then greeting them accordingly.

For instance, if someone enters the store in an unhurried, casual fashion, usually a simple hello or even just a smile and eye contact are an appropriate first contact. Many shoppers do not want to be helped right away even if they have a specific agenda.

But if someone appears rushed or more like they are ready for help, it would be appropriate to say hello and actually move toward them. If they have a questioning or searching expression, something like, "You look like someone on a mission" would be a good way to open the conversation.

In every case, let the customer break eye contact first. Frontliners don't need to follow customers around, but they should be tuned in to them and follow the customer's lead, always ready to respond. If your team's facial expressions and body language appear open and ready to help, customers will engage with them when ready.

-Heidi Macias is manager of Books of Hope at Community of Hope Lutheran Church in Rosemount, Minn.