For some solid intel that'll keep you looking your very best this summer, we asked a dozen men's grooming pros—the ones who comb and buff the likes of Ryan Gosling, The Weeknd, and Rami Malek—for their tips and advice on all things hair, skin, and body.

Being a well-groomed man is as much about avoiding tragic mistakes as it is performing tidying rituals. No matter how carefully you shave or how expertly you style your hair, if your toenails look like claws, you're back to square one. To help you see where you could be going wrong, we asked our team of Hollywood men's grooming pros to share their biggest no-nos. The main takeaway: Caring too much—or too little—is where most men go wrong. Also, f-ing with your eyebrows is risky business. Read their specific advice, below.

1. Being a grooming minimalist—to a fault.

“The biggest mistake I see men make is not using moisturizer on their face. Your skin needs hydration and protection from the sun!”—Barbara Guillaume, groomer to Jake Gyllenhaal and Edgar Ramirez

“I would love for men to understand the benefits of a manicure and pedicure. “—Losi, groomer to Orlando Bloom and Chris Hemsworth

“An unshaven neck is my pet peeve. Shaving your neck is the easiest way to extend a haircut. You can do it yourself with a trimmer or have a friend or partner do it! There’s no excuse.” —Cheri Keating, groomer to Tom Hiddleston and David Oyelowo

2. Or going a bit too far with your grooming routine.

“You don’t need night cream. If you have a great, hydrating face cream, that is more than enough to use at night. Don't be swayed into thinking that you need both.”—KC Fee, groomer to Luke Evans and Joel Edgerton

“Professional teeth whitening is too much, in my opinion. It’s rarely subtle. Flossing and brushing twice daily should do the trick. Should you want to do a little extra something for removing coffee or tea stains, brush with a paste made from baking soda and 2.5 to 3 percent food-grade hydrogen peroxide. You can do this a couple times a week. Alternatively, you can purchase ADA-approved whitening strips.”—Cheri Keating

“Don’t over-product your hair. I see a lot of guys using way too much hair product on their hair, where you can see flakes or white residue. It’s not necessary.—Carola Gonzalez, groomer to Michael B. Jordan and Milo Ventimiglia

3. Not embracing your grays in all their glory.

“When men are going gray, many of them tend to want to hide it by using hair color. Imagine if George Clooney dyed his hair—that would be tragic! George Clooney is a silver fox, and we love him for it. Salt and pepper can be super attractive and a whole lot better than a lousy dye job.”—Christine Nelli, groomer to Justin Timberlake and Ryan Gosling

“Lots of men in Hollywood like to cover their grays—it is so overrated! Gray hair is sexy and manly! To all the men out there using color on their hair or beard, STOP. Women love it!!”—Barbara Guillaume

4. Accidentally becoming “eyebrow guy.”

“Avoid threading your eyebrows. It’s fine to pluck stray hairs here and there or shape the eyebrows, but threading makes eyebrows look too perfect, and that’s not a sexy look on a man.”—Carola Gonzalez

“I don't love seeing overly shaped eyebrows on men. I think it makes the features more feminine, and though it's a big style statement in some countries, I can do without.”—Jhizet Panosian, groomer to Riz Ahmed and Donald Glover

“Improperly groomed eyebrows just stick out. Cutting them incorrectly may leave holes in the brow. And plucking out only the gray hairs leaves them looking patchy. Don’t do it!”—Losi

5. Getting stuck in a grooming rut.

“I'm not a huge fan of hair gel. I feel it's a bit dated and men still use it because it was such a staple in most households growing up. There are so many products on the market that can achieve a strong-hold look while leaving the hair looking more natural.”—Jhizet Panosian

“If you’re wearing the exact hairstyle for work and play, then you’re in a rut. I’m not recommending drastic transformation, but a subtle change to enhance your appearance will not go unnoticed. Use hair products to create one look that’s more conservative and one that’s more stylish.”—Kristan Serafino, groomer to Ryan Reynolds and Norman Reedus

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