Your college education may have been formal, but your attire during your years of study was probably anything but. Pre-graduation, dress codes are either non-existent or easily disregarded—and most of us know from experience that nobody's going to complain if you show up for finals wearing whatever you slept in the night before.

But in the working world, clothes matter more, especially if your job involves lots of face time with coworkers or clients. And even if your office doesn't have a written dress code, if your attire falls short of professional standards, there's nothing more awkward and embarrassing—for you and your boss—than being called in for your own private episode of What Not to Wear. Here's a rundown of how to choose your workwear and avoid any fashion faux pas.

1. IF YOU DON'T KNOW, LOOK AROUND; IF YOU STILL DON'T KNOW, ASK.

Many offices don't have an official dress code, the assumption being that employees will figure it out themselves. But if you can't figure it out by observing other employees during your interview (for which you should err on the side of formality, if not wear a full suit), then ask HR if there's a policy surrounding proper fashion. 

2. IF YOUR DRESS CODE IS "BUSINESS FORMAL," SUIT UP. 

Also sometimes called "boardroom attire," this is the fanciest and least flexible of professional fashion categories, usually reserved for upper management, accountants, lawyers, and entry-level folks who have a lot of contact with high-level execs.

Men should wear a suit, tie non-optional, and a pair of well-polished professional shoes with socks. (No sneakers, no sandals.) For women, a pantsuit or mid-length skirt suit, black or neutral closed-toe pumps, and a conservative blouse are your best bet, although you have a bit more flexibility in terms of cuts, styles, and color. Both sexes should keep flourishes to a minimum—a bold-colored tie, a modest necklace—hair should be neat, and makeup should be unobtrusive. Unless you know for sure that bare legs are de rigueur in your office, you'll want to wear pantyhose with your skirt. 

3. "PROFESSIONAL ATTIRE" IS JUST WANT IT SOUNDS LIKE. 

A "professional" dress code means a little more leeway to have fun dressing up, but it's still fairly staid. Guys should stick with dress pants and button-down shirts, but a sweater or sport coat can stand in for a suit jacket, if you like. Ties are officially optional, and color is back on the menu, within reason; a tasteful plaid or check shirt or a non-neutral sweater are fine. (Sorry, gents; your bright orange novelty tuxedo has to stay in your closet until Halloween.)

For women, a coordinated suit is no longer required, but you'll want to wear a conservative, subtle-colored dress, blouse, or sweater, with sleeves at least three-quarter length. You can also get a little more creative with jewelry and makeup, but it's still best to avoid anything too attention-grabbing (e.g. big sparkly statement necklaces, bright red lipstick). The good news: You no longer have to wear the most boring pair of pumps in your closet, and pantyhose are most likely optional. 

4. LET (A LITTLE) LOOSE IF YOUR DRESS CODE IS "CORPORATE CASUAL." 

Also called "business casual," this is the point at which employees of both sexes can sigh with relief and put their suits away. For women, short-sleeved and sleeveless tops are now acceptable as long as they're made of office-appropriate fabric and keep your decolletage relatively covered. Hemlines can climb a few inches above the knee; you can also wear a shift or shirtdress in a solid color, or a printed blouse or skirt as long as the pattern isn't too flashy.

For men, jackets are now entirely optional and ties are completely unnecessary; as long as your shirt is tucked in, you're fine. Khakis or chinos are also acceptable in lieu of dress pants, and while your shirt should still have a collar, a black, navy, or neutral-colored polo can stand in for a button-down. And if you've been dying to sport the loafers-with-no-socks look, here's where you can try it out.

5. FOR FULLY CASUAL OFFICES, JUST ABOUT ANYTHING GOES. 

Jeans at work? In a casual office, they (probably) don't mind if you do; just make sure you're not the only one sporting denim, and opt for your classiest pair. (Think: dark wash, nicely tailored, no rips or fraying.) Men, collared shirts are now optiona—though, if you're going to wear a tee, make sure it's clean and in good shape. For women, cropped pants (not tops), bold prints, and mid-thigh-length skirts are now okay. And as long as you're dressing for daytime and not the red carpet, your makeup and jewelry are yours to choose. In short: If you wouldn't be embarrassed to be seen in it by your grandparents, you can probably wear it to your casual workplace.

6. CREATIVE OFFICES MEAN MORE FUN WITH FASHION. 

If you work in a creative field—or just with a lot of creative people—then you've probably already noticed that your coworkers can get away with wearing things that might not fly in the average office. Worn jeans, vintage dresses, crazy colors, visible tattoos and piercings, hair colors not found in nature: All of these things may be welcome in your workplace, depending on where you are and what you do. And even in a more buttoned-up office, you'll likely discover after working there a while that certain dress code rules can be bent, if not broken. 

7. EVEN IN THE MOST CASUAL OR CREATIVE OFFICES, SOME ARTICLES OF CLOTHING ARE NEVER ACCEPTABLE. 

It should go without saying, but sports jerseys, evening gowns, exercise wear, pajamas, and any clothing that sports an offensive image or slogan are a bad idea no matter where you work. Ditto anything that gives your coworkers an unobstructed view of your undergarments. And even if your workplace is accepting of very casual or creative clothes, there should still be a discernible difference between your work attire and your loungewear: Stained, torn, and worn-out stuff gives the impression to your boss and coworkers that you're lazy and don't care.

And finally, a cardinal rule: 

8. UNLESS YOU'RE A CAMP COUNSELOR OR NATURE PROGRAM HOST, YOU SHOULD NOT BE WEARING JORTS TO WORK. 

Ever. 

All photos courtesy of iStock.