6 Timeless Lessons Celeb Beauty Products Have Forced Us to Learn

Monday morning, Niall Horan of One Direction tweeted a pic of his hands (did he take the photo with his feet? I'm going to go ahead and assume he took the photo with his feet), and said hands were decorated with eyeshadow, eyeliner, lipstick, and nail polish swatches. (I must say I am intrigued by that sparkly polish on his left ring finger. The story of my life: I'm a sucker for glitter.) The occasion? A new One Direction makeup line is in the works, and Horan tested out the goods on the backs of his paws. You could say he's a hands-on makeupreneur. (I'll see myself out.)

This is not 1D’s first foray into beauty products: The five pop stars are successful perfumeologists and in 2013, they developed a makeup line with MUA cosmetics. Furthermore, they happen to be experts in what makes you beautiful. (Sorry. Had to do it.) One Direction is in their element.

As makeup-savvy as 1D may be, it never hurts to look at what's worked (and what hasn't) for other celebs who have jumped into the makeup ring. Gotta keep learning, gotta stay sharp, et cetera. Here are six pieces of timeless wisdom gleaned from other celebrity makeup lines that One Direction—or anyone in the makeup making game, for that matter—can put in the back pocket of their skinny jeans:

Mary-Kate and Ashley by Mary-Kate and Ashley Olsen

Tip no. 1: Frosted eyeshadow is the best, cannot be denied, is appropriate in any given situation.

Fingertip Fetish by Adrienne Bailon

Jamie McCarthy/Getty Images Entertainment/Getty Images

Tip no. 2: Vegan nail polish exists, but that doesn't mean it's edible.

Khroma by Kim, Kourtney, and Khloe Kardashian

Kardashian KHROMA Beauty

Tip no. 3: When brainstorming the name, be sure to double-check it. Yes, even if you concocted a bizarre spelling.

Heidi Klum's Very Sexy Makeup Collection for Victoria's Secret

Gabriela Maj/Getty Images Entertainment/Getty Images

Tip no. 4: No one will be mad at a chocolate-flavored lipgloss.

Rihanna for MAC Cosmetics

Tip no. 5: If you wish hard enough, red lipstick will grow wings and fly right off of the shelves. BIRD LIPSTICK!

One Direction's Little Things By MUA

Stuart C. Wilson/Getty Images Entertainment/Getty Images

Tip no. 6: What could be better than a new bottle of nail polish? A new bottle of nail polish that comes with a 1D guitar pick, that's what.

Ugh, so many pearls of wisdom. I definitely need to replenish my frosted eyeshadow supply. It cannot be denied!