It doesn't really require a lot of technology to sell a customer a burger. Take order, flip burger, and serve it on a bun with a side of fries, right?

But that's what any burger joint can do. The great ones are the restaurants that make the interaction more memorable and personal--and that's precisely where technology can help.

The trick is figuring out the best way to use it. "The moment you tell me technology should be used to eliminate people, I don't want to be a part of it," says restaurateur and Shake Shack founder Danny Meyer.

Meyer joined Warby Parker co-founder Neil Blumenthal on Tuesday at the Fast Company Innovation Festival for a discussion on how their respective companies have incorporated new innovations that improve the customer experience.

Here are five takeaways from the two entrepreneurs on high-tech ways to keep your customers happy.

1. Use social media to play both defense and offense.

It's a given that you should respond directly to customers who complain about your brand on social media. But that responsiveness doesn't always have to come when your company is on the defensive.

Some of Meyer's most hardcore fans have taken to visiting all of his various New York City restaurants--Gramercy Tavern, Union Square Cafe, Blue Smoke--in one several-day trip. A couple once flew in and, having heard about the Shake Shack at JFK airport, planned on visiting the restaurant on their way out. When they returned to the airport for their flight home, they realized the Shake Shack was in a different terminal and tweeted their sadness. Shake Shack spotted the tweet, took the couple's orders, and made a special delivery to them from across the airport.

2. Focus on the important interactions.

In its brick and mortar stores, Blumenthal says, Warby Parker uses technology to "eliminate low-value interactions and amplify high-value ones." Customers type their delivery addresses into tablets on their own, but employees are active in helping the customer find the right pair of glasses. The company even films such interactions to make sure workers don't spend too much of a conversation looking down at a tablet or computer. If they do, it's the perfect opportunity for some training.

3. Respond to customers personally and in real time.

Warby Parker has been known to make videos and upload them to YouTube in response to customer questions. Its live chat feature is sometimes a team effort. Recently when a customer was dropping Lord of the Rings references, the employee on the other end, who had never read the books, tapped a new representative to take over and continue the Tolkien-themed banter.

Shake Shack's teams often respond to complaints on social media mid-meal so the staff can address the issues. "It's a huge improvement over the days of snail mail, when we'd find out two weeks later, after the customer had told 30 or 40 other people," Meyer says.

4. Get to know your individual customers.

Meyer's restaurants have been customizing customer experiences since long before technology came around. Before, it meant remembering a face or name, then passing that customer's preferences along to the server--but that left plenty of holes. Check-in platforms like OpenTable and Resy tip off Meyer's restaurants ahead of time as to who's coming in that night. So a server might mention that he knows a customer doesn't like Parmesan cheese. Or, if a customer on an upcoming reservation usually drinks a certain type of wine that's currently out of stock, the restaurant might send someone out to get more.

5. Use just the right amount of technology.

When the Union Square Cafe reopens later this month, keen-eyed customers will notice something on the wrists of employees: Apple Watches. Servers won't be using them to input orders, since Meyer believes that would create too much of a distraction. The devices will be used to improve communication on the floor: Managers will be able to ping hosts to let them know a table has been re-seated; the coat check can be notified once a table's check is paid to let them know the guests are on their way.

There is one type of technology that Meyer doesn't see his establishments using: augmented reality glasses. "You don't want another layer between the employee and the customer," he says. "The surest way to the heart is with eye contact."