We all want to dress to impress, but therein lies the complication: An impressive outfit in one context might be ridiculous in another. Fortunately, simple guidelines exist for making a good impression on just about anyone, in just about any scenario. Here's what to wear to look your best...

1. AT A JOB INTERVIEW

Unless you're applying to work in the kind of office where you'll be dinged for appearing too stodgy or buttoned-up, a suit should always be your go-to job interview attire—even if it's the only time you ever wear one. A nicely-fitted suit projects professionalism and suggests that you know your stuff, even before you open your mouth. And if you stumble on a question or two, a polished appearance may buy you some benefit-of-the-doubt from your interviewer.

2. AT A NETWORKING EVENT

If you're schmoozing for contacts outside the office, you'll want people to approach and remember you—and to dress accordingly, so that you look professional and polished without fading unmemorably into the crowd. For guys, this is a good time to pair your usual pants and jacket with a more colorful shirt and tie: not so bright that it clashes or looks clownish, but with enough punch that you'll stand out a bit in a sea of suits. For ladies, it's an opportunity to break out some bolder lipstick or an eye-catching statement necklace that are a little too much for daytime at the office, but great for making a lasting, professional impression after hours.

3. TO YOUR SIGNIFICANT OTHER OR SPOUSE'S OFFICE PARTY

The great thing about being a corporate plus-one is that you won't suffer any consequences for wearing something inappropriate. Unfortunately, however, your date might be judged for your fashion faux pas, which is why it's a good idea to err on the conservative side with what you wear. Guys, as always, can't go wrong with a suit or sport coat and button-down shirt; just leave your novelty tie at home. For women, bust out that little black dress (as long as it's not too little), and save the fun self-expression for your shoes and/or jewelry.

4. ON A FIRST DATE

When dressing to impress on a date, it's important to look nice—but it's just as important to look like yourself. Showing up in a bespoke suit or a glamorous bodycon dress is great, but only if that's typical of your going-out style (and if your date is to a fancy dinner, not the batting cages). The best impression you can make on your date is an authentic one. A good way to make sure you're doing that: Grab a selection of your favorite outfits first—the things you love and wear all the time—and then choose one appropriate to your date venue from there.

5. WHEN YOU'RE HAVING DINNER WITH YOUR SO'S PARENTS FOR THE FIRST TIME

If you want your SO's parents to like you, it can be tempting to dress up as someone you think they're most likely to approve of. (Raise your hand if you own an excruciatingly classy sweater set and pearls just for this purpose.) But much as with first-date-wear, it's better to choose an outfit that's meet-the-parents appropriate but still gives some sense of who you are, especially if they're going to find out anyway when you become part of the family.

For most meet-the-folks scenarios, you can't go wrong with a favorite, flattering outfit that's on the more modest and dressier (unless you know you're dining somewhere super-casual) end of the spectrum. And since your future in-laws are likely to compliment you on whatever you wear, you might want to consider cufflinks (for guys) or a piece of jewelry (for girls) with a little family history, if you have one. It'll give you something to talk about if the conversation is slow to start.

6. AS A PUBLIC SPEAKER

Whether you're addressing an audience of hundreds, presenting to a board of 20, or moderating a panel of five, what you wear to speak in public depends first and foremost on where you're giving it and to whom. As a general rule, you want to be as dressed-up as the best-dressed person in the room. For men, this usually means either a suit or a pants-and-sportcoat combo, tie optional. For women, anything from a pantsuit to a dress to a nicely-fitted tee and dress pants may be appropriate. (Of course, if you're a celebrity guest speaking to a room full of adoring fans, you can wear basically anything you want—lucky you.)

Solid colors are best for projecting authority; avoid twee prints or distracting accessories, especially if you tend to fiddle with them. And if you choose to wear a skirt, keep your hemline in mind: If you're standing above a crowd, they may get quite a view if it hits at the knees or above. 

7. FOR YOUR FIRST DAY AT A NEW JOB

First and foremost, let your office dress code and/or some discreet observation of your fellow employees be your guide; you'll have plenty of time to push the fashion envelope once you have a better sense of your workplace norms. Beyond that, the best first-day-of-work outfit is one that makes you look confident, at ease, and focused. The average first day on the job involves lots of walking around, meeting new people, and setting-up of your workspace. Aim to wear shoes you can walk comfortably in, fabric that doesn't scratch or snag, and a top that gives you a full range of motion if you need to reach something overhead. Above all, make sure your first-day-of-work clothes fit you well; you don't want to have to fuss with your buttons all day (or worse, have a wardrobe malfunction in front of the CEO).