"How to dress for interview success" is a frequently requested topic in the workshops and support groups I conduct. Here are a few strategic suggestions on looking your professional best, no matter your shape, size, gender, or age:
If the job is a major step up for you: Dress the part. If that means borrowing a great watch and/or investing in a fabulous new suit and shoe leather, then do it. Don't forget to check out factory outlet and thrift shops for real deals. Be prepared to mix and match so you'll have enough outfits for multiple interviews.
If the job represents a step down: If you don't want to be the VP of Sales any more, don't strut into the interview wearing a designer suit and power tie. Tone it down and dress more casually -in a sports coat and dress shirt without a tie, or a shirt and tie sans jacket, or a high-quality knit polo with crisply pressed khakis.
If you feel you are perceived as too young: Wear a serious suit, quality accessories, and add a sharp-looking pair of glasses (non-prescription models are available for whippersnappers with 20/20 vision). Oh, and consider losing the spiky hairdo and goatee.
If you worry you'll be viewed as too old: Ask a few pros about the best way to update your hairstyle (in my humble opinion, shorter is always better for men who are gray or balding). Neither men nor women absolutely have to sport that gray if they don't want to - there are plenty of roads back to your original hair color - just use your best judgment. Make sure your eyeglasses don't date back to the 70s or 80s (think how spiffy you'll look with a smart pair of glasses in the new high-tech materials). You might also want to consider dressing a notch or two more casually.
If you're overweight: Make sure your garments are high-quality and well-fitted. Stand straight and tall. Seek expert assistance with a reputable retailer specializing in larger sizes. Go for color contrasts that result in slimming vertical lines, such as a darker shirt with a lighter-colored jacket or vice-versa. Add a splash of your favorite color to bring attention to your face via a silk necktie or scarf.
If you're an underweight man: Consult with a smart tailor as to how to combine layers of clothing, well-starched shirts, shoulder pads, generous cuts, and more substantial fabrics to bulk up a bit.
If you're a curvaceous woman: Don't flaunt it or you'll risk being hired (or not) based on appearance. Avoid body-conscious knits, tight or short skirts, and anything even remotely resembling a peek at your cleavage. If you're ample-busted, be sure to wear a jacket. Make sure your clothes fit well and are attractive, but not seductive.
Stop making strong scents: Your well-scrubbed self should generate a pleasing, subtle scent that won't burn the eyes of the interviewer. Skip the perfume and cologne altogether, please! Don't smoke on the way to the interview, ever! Brush, gargle, and use breath spray, please!
Be a charming chameleon: Use the target company's color as your accent color if possible.
If in doubt of what to wear for a given interview, ASK your interviewer ahead of time. Companies these days vary dramatically in conservatism of dress. In some of today's entrepreneurial environments, the top folks may be sporting shorts and flip flops when they interview you - asking ahead of time ensures you don't show up looking like a dork in a three-piece suit. Questions about how people dress for a normal day on the job versus a big client presentation day should be a part of your pre-interview intelligence gathering. Oh, and once you have the job, emulate the dress of those who currently hold your next position.
Last but not least - I'm astonished at the number of clients who obsess about appearances but otherwise fail to prepare for the interview. Do your homework on the company so that you'll have a targeted interview agenda to go with that sharp get-up.