When it comes to discussing fashion trends, there’s no one better to tell us what’s in and what’s out than stylist Brad Goreski. When he’s not critiquing the outfits of Hollywood’s leading ladies on E’s Fashion Police, he styles a very A-list crew, including Jenna Dewan Tatum, Lea Michele and Kaley Cuoco. So when we caught up with him at the opening of Marshalls new N.Y.C. Tribeca location, we had to get down to business: What exactly should we buy for summer?

According to the stylist, there are three trends that are definitely worth investing in. First, he says that mules are replacing the ballet flat. “I think that slipper look is really cool with a pair of denim cutoffs and a great T-shirt.” He also says florals are a trend both men and women should be wearing.

But the easiest outfit to wear this summer has to be the Canadian tuxedo. “Denim on denim — I think the look is so cool. Adding a little neck scarf, or some jewelry or running shoes — that whole look is really easy to do,” Goreski advises. “So investing in a great denim shirt or really good denim jacket is worth it.”

Before you start your summer shopping, Goreski shares that sandals, swimsuits and designer beach towels are definitely not worth spending a whole paycheck on. (That’s what Marshalls is for!) But when it comes to sunglasses and coverups, going big is totally worth it. “Beach coverups can go with jeans or you can wear it as a dress. You can dress it up, you can dress it down, I would say splurge.”

RELATED PHOTOS: The 7 Hottest Swimsuit Trends of the Summer (And Where to Buy Them!)

But let’s be real, all of these styling tips will mean nothing if you can’t share your #OOTD on Instagram. And no one does a better wall-leaning pose or outfit mirror selfie than Goreski. In fact, his recent Mexican getaway was so envy-inducing, that we had to get his expert posing tips to use on our next beachy vacay.

FROM PEN: Ryan Seacrest is Already a Fixture in Kelly Ripa’s House

“You have to take it at the time of the day when the lighting is right,” he explains. “If the sun’s not in the right position you can have too much shadow, but you also want a little bit of shadow because the natural daylight does a really good job of showing off your body. I watch the beach and see where the sun is at the best time of the day. Magic hour is always a great time to take a photo.”

Another way to get the perfect Instagram pic is having a significant other take it for you! He says his fiancé, TV writer and producer Gary Janetti, is a “very good sport” and the ultimate Instagram boyfriend.

“He doesn’t love taking photos of me. I’m always like, ‘Lets’ do it here, you have to be at this angle.’ In one of my Insta stories he said ‘Can we please stop taking pictures and video taping food while we’re here?’”

While his vacay photos are courtesy Janetti, he usually improvises on the day-to-day. “I will stop strangers on the street,” he says in his effort for the perfect Instagram. “I’m also a big fan of the selfie timer.”

What are you excited to buy this summer?