One of the main purposes of an interview is to present yourself to a potential employer in a manner that reflects a highly polished and professional image. The first judgment an interviewer makes is going to be based on how you look and what you are wearing. The first impression you make on a potential employer is the most important one. That's why it's always important to dress professionally for a job interview, even if the work environment is casual.
You'll want that first impression to be not just a good one, but, a great one. The candidate dressed in a suit and tie is going to make a much better impression than the candidate dressed in scruffy jeans and a t-shirt.
For Men
Here are some things that a man must not forget for the interview. Belt, tie, dark socks, conservative leather shoes, neat & professional hairstyle, neatly trimmed nails, portfolio or briefcase.
A conservative business suit is almost always the rule. A well-tailored or fitted suit coat and trousers will go a long way in helping you present yourself professionally and confidently. Acceptable colors continue to be darker shades and hues including grays, blues (navy), and black. Pattern designs such as pin stripes and plaids are acceptable as long as they are subtle.
Although, a plain white or off-white shirt is always a winner. Dressing in your best attire for the interview also means having your shoes shined, if not new. Wearing a new suit and tie with an old, dirty pair of shoes that need resoled would be like bad for the interview. Laced shoes are the general rule; loafers are a little too casual. The color of your socks should complement or match the rest of your outfit. See-through socks are not considered appropriate. Likewise, a leather belt that matches the color of your shoes and has a small buckle is a good choice.
For Women
Dressing in a conservative business suit is the best way to present a professional image. As has been stated, the suit should fit well and make you feel good about yourself. Ask clothing salespersons for assistance in determining what is currently acceptable for skirt length; generally, length should not be too long nor too short. You should be able to sit comfortably wearing that skirt
The grays and blues are standard; women tend to be able to get away with wearing more of a variety of colors. Oftentimes, bright colors including reds, maroon, and various shades of blue and even green are acceptable. Women are also usually able to wear various fabrics without appearing unprofessional.
Your blouse should complement the suit in a conservative fashion. It should not be too revealing, high around the neck, nor have too many ruffles or frills. See-through blouses are discouraged for the professional interview. Stockings are a must and should be flesh-toned or colors very close to it. Avoid color or patterns that would be distracting.
Shoes should be sensibly selected in a way that is not intended to make a statement. High heels and open toes are to be avoided.