Everything We Know About Fashion We Learned From the Mary-Kate and Ashley Movies

When you don't know what to be for Halloween, the classic witch works every time.

Please only wear tights that accent your plaid print.

Your Western-inspired look is never complete without a little fringe.

Never settle for a dress code. Even when your sister is black-tie-ready, you can still totally go in a baseball cap.

There are plenty of variations of overalls. No matter which pair you choose, know that you'll look cuter with a flannel tied around your waist.

Round retro sunglasses: always a necessity.

Your casual spaghetti-strap tank top just isn't complete without a choker necklace.

Your closet should always be stocked with a floral minidress. They'll come in handy at a moment's notice.

If you're going to go matchy-matchy, you might as well go all out.

They call them biker jackets for a reason. Oh, and platform low-tops will always be cool.

When you're wearing a bandanna, it's just easier to keep your cool.

Don't leave the house without adding a simple style quirk, i.e. clasping your cardigan with the top button only.

Wearing your denim jacket inside is highly encouraged. After all, it's part of a complete outfit.

Bandanna headbands and easy caps are perfect for brunch.

Board shorts are sexier than a bikini. Every time.

Graphic tees are a weekend-wardrobe staple.

If you've got it, flaunt it — at least when you're on the beach.

Warm accents heat up your beach-ready look.

When you're traveling to a new place, always go equipped with hats and scarves. You can shed your layers later.

It's impossible to stand out with a plain-old black umbrella.

Always pack a pair of shorts to wear to the beach. Who wants her booty on full display in the middle of the hotel lobby?

A plunging neckline does not equal faster service. "Take a number," Megan Fox. We mean Brianna.

Plaid button-up tanks are cool. Studded plaid button-up tanks are cooler.

Never let anyone tell you that you don't look sleek in your turtleneck.

We don't want to make generalizations, but there are a ton of guys who are most attracted to the girls in simple looks. Sometimes, a crisp white button-down and flared jeans is all you need.

Beaded wrap bracelets and necklaces play up your beachy glow at sunset.

Oversize sweatshirts are totally campfire appropriate. Don't let anyone tell you otherwise.

I "Heart" NY shirts are a classic, whether dirty or clean.

Feel free to cause a scene in the middle of Times Square, especially if you're dressed to the nines.

When in New York, pile on the diamonds and make a flashy statement. PS In this city, a puppy counts as a street style accessory.

You can scrunch your nose at your sister's fashion choices, but that doesn't mean you can't share a cab.

Distressed denim + graphic tee + statement hat + hobo satchel = grungy cool.

Every girl must master her #IWokeUpLikeThis look.