You know those online reviews you read on websites like yelp.com, amazon.com and Google Local? They often seem too good to be true.

That’s because sometimes they are.

New York state’s attorney general recently announced a settlement in which 19 companies will pay $350,000 in penalties for writing fake online reviews for restaurants, nightclubs and other businesses.

These fake reviews — which appeared to be written by actual customers — praised these businesses and encouraged other to shop or dine there.

“Consumers rely on reviews from their peers to make daily purchasing decisions on anything from food and clothing to recreation and sightseeing,” said Eric Schneiderman, New York state attorney general. “This investigation into large-scale, intentional deceit across the Internet tells us that we should approach online reviews with caution.”

The technology research firm Gartner Inc. predicted that up to 15 percent of social media reviews posted in 2014 will be fake or paid.

So how can you determine what is real and what is fake when looking at online reviews?

Here are some tips courtesy of Trackur, an online reputation and social media training website:

Pay attention. Look for someone posting multiple reviews in a short period of time, especially if they are strongly positive or negative.

Check the date. If the post was made before the restaurant opened for business or the new soft drink appeared on grocery shelves, it’s probably fake.

Look at other reviews. Check the user’s profile if you can and see what other reviews he or she has posted. If they are all praise or complaints about a specific establishment or product, they are likely fake or paid.

Beware of all-positive or all-negative reviews. Most real reviews will have some good and bad things to say about a product or establishment. If the review is 100 percent positive or negative, you might want to check it more closely.

Check the jargon. Reviews written by businesses often use industry jargon, like “guest accommodations” and “delectable cuisine.” Real people don’t use those phrases.

Watch out for “customerjacking.” It’s when reviewers writes that they hated a particular place or product and that a certain competitor is much better.

They often include a link to see what the competitor is offering.