From the girl who sits in front of you in class with the dangerously low jeans to pictures we see of celebrities like Britney Spears and Paris Hilton, it is clear what we wear under our clothes doesn't always remain our business.

For those women who often fret over what to put on before donning their outfit for the day, there are some basic guidelines to keep in mind so that whatever the occasion, others won't be distracted by your undies faux pas.

What to wear ...

Under dress clothes

"It's really going to depend on the fabric of the item," said Shannon Greenwood, store manager at Victoria's Secret in Manhattan Town Center.

For more formal occasions where one would be wearing a dress, skirt or nice slacks, Greenwood recommended women wear something seamless, like a thong or seamless panty that will prevent a visible line.

No matter your choice, however, take care to buy the correct size, she said.

"Proper fit, also, is as important as style," she said.

Under casual bottoms

Most women tend to wear what they find most comfortable under more casual bottoms like jeans.

Greenwood said bikini style underwear are a popular choice.

"Jeans are more forgiving, so you have more of an option as to what you can wear," she said. "But a lot of people also opt for thongs, which are very popular. I think a lot of women just really like how they look when they wear thongs, and how they work under their clothes."

Under white bottoms

A common problem posed by a popular warm-weather trend is what to wear under white bottoms. Though one's first guess might be to pull on something white, Greenwood said that is not the best option. A skin tone, or nude, is probably the best option as far as color goes, she said. A nude thong probably would work best, depending on the material of the bottoms. Another choice would be nude boy shorts.

"Even opting for a footless hosiery with a built-in panty would work great," Greenwood said. "It would give you a smooth line."

Under white shirts

The nude shade rule also applies for bras, Greenwood said.

A white bra isn't a good option because it easily shows through, because white differs so starkly from skin tones.

"I know in Hollywood it was trendy for awhile to wear a bra that you could see (through your clothes), but we're in the Midwest," Greenwood said. "We're more conservative, so the best thing to do is find a bra that's closest to your skin tone."

Under casual tops

Most basic, built-for-comfort bras are great for wearing to class or hanging out at home, Greenwood said.

A good option for everyday wear also would be something seamless.

When heading out on the town, however, most women might want to choose something fancier or more cleavage-enhancing, she said.