Mistakes in the attire and personal-appearance department when you work in sales can easily make prospects uneasy and decrease their trust in you, even if the effect is subtle or subconscious. Follow these five timeless (but often forgotten) tips to make sure your appearance sends the right message.

1. Dress like your customer.

People trust and want to associate with people who are like themselves. With that in mind, match your attire to that of the customer. If you're meeting with a casual customer in a laid-back setting, dial down your wardrobe. If you're headed to the corner office, opt for the more formal end of the spectrum. (And it goes without saying that your clothing, even in the most casual of situations, should never be suggestive.)

2. Think locally.

In line with the first rule, keep your dress in tune with the part of the country you're in, as the unwritten standards of dress tend to change from place to place. At one point in my career, my sales territory included Southern California and Nevada; in California, my customers nearly all wore business suits, but in Nevada, they dressed much more casually. When I traveled, I packed both types of clothing, so I could match my attire to the state I was in.

3. Stay neat.

Whether you're at the casual or formal end of the spectrum, staying neat at all times is a must. Always do a quick mirror check in the restroom before a meeting to make sure you look presentable. It does make a difference to prospects. I once had a good customer who wouldn't give a male rep a second appointment unless his shoes were polished, his rationale being that anyone with unpolished shoes was sloppy and wouldn't be efficient in business.

4. Beware of offensive odors.

You would think a rule as basic as this would go without saying, but I'm always amazed by how many violate it, whether it's with alcohol, heavy colognes and perfumes, or plain old bad breath and body odor. Avoid anything that could give you or your clothes a pungent scent before meeting with a prospect. I once had a sales rep call on me who reeked so badly of garlic that I couldn't focus on his presentation. That was 20 years ago, and I still remember it as if it were yesterday.

5. Don't smoke.

Cigars and cigarettes aren't the business fixture they once were, but never smoke before or on a sales call--even if your prospect is smoking. The smell lingers on your clothing, and the act of smoking tends to divert your attention from making the best presentation possible.

Keep the odds in your favor by following these basic rules of appearance and dress. A single violation can derail a sale quicker than you imagine!