As company profit margins teeter on the pessimistic side, job candidates need to present themselves with optimism. And that means style.

Job interviews are not plentiful, so candidates looking to succeed should take a second and third look in the mirror before heading out to make their case that they will be the company's next most valuable player.

There is truth to the adage: In a down economy, dress up.

"What you wear says something about the level of importance you are giving to the occasion," said Lynn Wittelss, the president and chief executive officer of the new Jewish Community Center in St. Louis. "If I dress up, it says that I thought about this, and I wanted to dress up because I wanted to show you how important I think this is."

You don't want to go overboard, but everyone would do well to avoid looking too casual or too dated. You don't have to look like a fashionista to get a job, but a first impression that says you mean business and you are up on the times could be especially helpful.

If you're younger and need to convey seriousness and depth, a look that's too casual can thwart that perception. If you're older and want to convey that you're still youthful and up-on-the-times, then a dated appearance can speak louder than words.

"The bottom line is that you want to leave the interviewer with a positive and lasting impression," said Suzanne Murdoch, who manages a team of career consultants at the Impact Group of St. Louis. She said the way you dress can leave that kind of impression. They might not remember your name, but they might remember the well-spoken woman with the red scarf.

However, Murdoch said you should dress in a way that's not distracting for the interviewer or for yourself. If you're self-conscious about what you have on because it's too formal or revealing, then it's going to show. And if the interviewer is too puzzled by your collage of shiny rhinestone brooches to look you in the eye as you talk, then that's not the lasting impression you're seeking.

Murdoch said men have an easier time because they can just slip on the male uniform of suit and tie or slacks and a shirt without much fretting. Women on the other hand "are so much more emotionally connected to clothing," she said.

When it comes to competing for a job, the key is confidence. If you feel comfortable and attractive, it will make you feel more confident, Murdoch explained.

Wittelss agreed: "I feel different when I'm dressed up in general, and to take that to the next level, I think that when you dress up, you feel more on your game. It's an old-fashioned concept, but it's kind of true."

Murdoch and Wittelss said everyone should consider wearing something that boosts their confidence as an easy performance enhancer. If you have a power color, wear it. If you have a favorite accessory that is part security blanket and part talisman, don't leave home without it.

Murdoch noted if you don't normally go for manicures, do it before an interview. The interviewer probably won't notice, but you will, and it might be enough to give you a boost. On the other hand, if you look down and see that your polish is chipped or your cuticles are unkept, it can be like a confidence erasure. You don't want anything to zap your self-esteem or throw you off your game.

Different jobs hold different levels of expectation, but some things are universal. Looking appropriate is one thing. Looking like a clone is another. She said it is important to project some individuality.

This leads us to the rules.

Dress like you, but better

You don't have to fake some contemporary chic look, but think of it this way: At an interview, you are expected to dress better than usual because you are expected to be on your very best behavior.

When in doubt, err on

the conservative side

Looking bland is never a good compromise, but if you're second-guessing whether something is suitable enough, such as a sleeveless top, denim pants or green nail polish, then don't do it.

Don't wear all black

It can be chic but also aloof. Nicolette Prpa of ShopSheBoutique.com said: "Wearing all black … can make you appear too standoffish or give the impression of wanting power. Opt instead for navy blue, beige or grey instead, which are safer options to giving a great first impression."

The pantyhose conundrum

Wittels said that although you don't want someone to be a fuddy-duddy, wearing or not wearing pantyhose can still be tricky. If you have nice legs, then it's probably OK to go bare in most situations. But your skirt should probably not be shorter than knee-length. If you're in doubt, opt for a longer skirt or pants. Please note that you should investigate the corporate culture on this. Anderson Minor, a human resource manager at Boeing, recommends wearing pantyhose. And some businesses, such as the Four Seasons St. Louis, require them of female employees baring their legs.

Be personable, not loud

It's OK to make one bold statement with a scarf, necklace or the collar peaking out from under your jacket, but you don't want your outfit to be outlandish. The look can convey that you're difficult to relate to.

Be sensible with shoes

Heels should probably stop at about 3 inches for an interview situation. And don't opt for anything too strappy or fussy with rivets or buckles unless you're entering a creative field where that kind of look might be appreciated. You came for business; you want shoes that look comfortable enough to spend eight hours in.

Don't forget the details

Make sure your clothes are wrinkle-free, remove chipped nail polish (a nice clear coat is a safe bet), buff your shoes with a cloth, don't take the purse that looks like a feed bag, and leave the signature scent at home. You never know how the interviewer will react. Trust us: The smell of desperation is not a good lasting impression.