No-no’s are a T-shirt, especially with a slogan or graphic on it; jeans, unless the dress code allows it; and sport sandals or flip flops. Men’s fashion is moving away from casual dress and toward the business suit.

MCT / Sara A. Fajardo Sara A. Fajardo

RALEIGH, N.C. — All those late nights at the office. All those times you volunteered to lead committees, work weekends, go to conferences.

They might help you snag that big promotion.

But those jingle-jangle earrings? The Fu Manchu mustache? Your hairstyle from the late 90s?

They could be hurting your chances of getting that corner office.

“Our image can tell others that we are creative or dependable or conservative or all of those and more,” said image consultant Carolyn Gustafson, owner of Image Strategy for Men & Women in Cary, N.C. “We make quick decisions about people based on their appearance. Whether or not that’s right, that’s the reality of it. We can’t wear our resumé around our neck.”

How someone is dressed was the third most important attribute in getting a new job, according to a study by Syracuse University and Total Executive Inc. of 300 executive recruiters, chief executives and directors of personnel. That’s behind communication and presentation skills.

Executives surveyed by TheLadders.com, a Web site for job seekers looking for six-figure salaries, last year said employees who dress casually at work seemed more creative and fun. But almost half of the 2,245 executives said those casual dressers risk being taken less seriously.

It’s enough to make you cringe, that something as small as wearing flat shoes instead of heels or your oversize, gadgety watch can hold you back.

But it’s more than just an image. When you’re polished and professional at work, “It shows you know the rules. It says, ‘I play by the rules,’ ” Gustafson said. “The decision is almost always made in the first few minutes. If you look the part, you’ll likely get the part.”

Certainly, style and fashion are subjective, and sometimes, taste differences are subtle.

The trick is knowing basic rules about what is appropriate for which work settings.

“If you show up to an advertising agency in a traditional blue suit, that’s going to work against you,” she said.

The same is true if you show up at a conservative bank in a short skirt and open-toed shoes without pantyhose.

Once you know the look that’s appropriate for your office, be consistent, experts say.

“When you have a consistent look, your co-workers expect you to act a certain way and look a certain way,” said Kate Leser, owner of A Distinctive Image, an image and wardrobe consulting company in Raleigh, N.C.