The 3 biggest mistakes people make in online dating, according to the CEO of eHarmony

Showcasing your best qualities in the real world can be tough enough; but online you're expected to highlight them solely through a few paragraphs and pictures. What could go wrong?

Grant Langston, CEO of the online-dating site eHarmony, recently spoke with Business Insider about the biggest mistakes people make in online dating — and how they can correct them.

1. Playing it safe — and coming off boring

Years of online matchmaking have taught Langston that too many people who are new to online dating (and even some who've been in the game a while) are deathly afraid of being perceived as weird. As a result, they build profiles that are downright boring.

It's not interesting to write "I like movies" in your profile, he says. Everyone likes movies. You need something to catch other users' eye if your profile is the 20th they've seen that day.

"I need to know that you like 'The Godfather' and you've seen it fifty times, and you can quote the dialogue, and your second-favorite movie is 'Tommy Boy,'" he says. "I need details."

Not only do details make you stand out (even at the expense of coming off goofy), but juicy bits of information lead to richer interactions if you end up going on a date.

"When I say to you, 'Now, 'Tommy Boy,' why on Earth do you like that movie?' that sets you up to talk to me," Langston says, "and it's a shortcut to a better conversation."

2. Telling an entire life story in one long bio

At the other end of the spectrum are people who don't know when to stop talking about themselves. Either they think they're endlessly fascinating, or they're just too dense to realize they're oversharing.

Even if the information is interesting, Langston says, people should exercise some restraint in sharing heaps of personal stuff too quickly. Listing a few movies you're into is good. Listing your entire collection, alphabetically by director — that's excessive.

"Leave something for the date," he says. "I don't want a dissertation about your film habits."

3. Settling for a photo that isnt well-lit and in-focus

Cell-phone cameras have come a long way in the past decade, but Langston says most people are still surprisingly bad at taking a flattering photo of themselves. Men seem to be especially fine with using (what seem to be) hastily-snapped selfies taken at odd angles, he says.

"The fact is, everyone puts a big emphasis on what they see there. And if what they see there is not good, they just won't go any further," he says.

The success of dating apps like Tinder and Bumble only emphasize that point, Langston adds. People who are looking for serious relationships might say they care about a deeper connection, but physical attraction always matters.

"Some people think that's shallow," he said. "That's just the human animal."