Good first impressions are crucial to landing a job. Your level of success will be determined by your bosses, who will begin your evaluation based on several non-verbal cues, such as the style, fit, color and cleanliness of your clothes; your choice of accessories; the firmness of your handshake; your posture; the manner in which you carry yourself; and the degree of your eye contact, enthusiasm and confidence.

The clothing you select is a key indicator of your respect for the interviewers (and the company they represent) as well as how seriously you take the interview itself. The better you dress, the more seriously you will be taken and considered. Not dressing professionally could be taken as an insult or offense.
 
General Tips Checklist

Wear professional and conservative clothing. Choose apparel that has received favorable feedback from people who are knowledgeable about the industry standard or specific company policy.
Ensure that clothing is clean, pressed and well-fitted.
Wear conservative (dark) shoes that are clean and polished.
Choose accessories that complement your clothing rather than distract from it.
Remove facial and body piercings.
Cover visible tattoos to avoid distraction.
Keep fragrances and jewelry minimal.
Make sure your hair is clean and conservative in color and style.
Less is more. Keep your look simple but classy until you become accustomed to the environment and learn about the company’s dress code.

Tips for Women

Acceptable dress includes a suit (skirt or slacks) or conservatively tailored dress.
Traditionally, skirts should be knee-length. Slightly shorter or longer are also acceptable.
Avoid blouses or sweaters that are transparent, tight fitting, have low necklines, revealing waistlines or details that detract from your face. Typically, arms are covered at least to the biceps and often to the wrist.
Always wear plain-style, non-patterned hose to interviews. The color should flatter your skin tone. A neutral color is always safe. For some industries, you may choose to wear hose that coordinates with your skirt. Carry an extra pair in case of runs.
Perfume should never be strong. A fragrance can cause an allergic reaction or offend the interviewer. When in doubt, do not wear perfume.
Apply natural-looking makeup and clear nail polish. This keeps the focus on the interview.
Do not carry a purse with a briefcase. Choose one or the other.
Wear flat shoes or low pumps in colors that avoid making your feet a focal point. Be sure your shoes are clean and polished. Avoid shoes that hinder walking fast. This lowers credibility. Avoid open-toed shoes since they are often associated with social agendas.

Accessories express your personality and accentuate your best features. Keep it simple! Women in general tend to wear too many accessories, such as earrings, necklaces and rings. At the same time, these can accentuate your personality and can be an asset if worn in moderation. Avoid dangling earrings, and wear no more than one ring per hand and a dress watch.
 
Tips for Men
Wear a matching suit in navy, black or gray (pinstripe or solid), or a navy blazer and gray dress slacks.
Select a white or a light blue dress shirt that contrasts with the jacket and/or tie. Typically, arms should be covered to the wrist. Exposing arms by rolling up your sleeves is interpreted as less powerful and is less formal.
Ties should be silk or silk-like and should coordinate with the jacket and pants, but choose one that strongly contrasts with the color of your shirt; selecting subtle or simple patterns enhances credibility. Be careful in tying the knot – the half-windsor is recommended.
Socks should be calf-length or above the calf. Choose colors such as dark blue, black or gray.
Select lace-up (not slip-on) dress shoes. The color should be dark or should blend with your pants.
Select a leather belt that visually blends with or matches your shoes.
A short hair cut and no facial hair is expected.
Minimize jewelry. Avoid a necklace. Wear no more than one ring per hand and a dress watch.
A full-length coat can be worn over your suit, but avoid casual coats.
Cologne should never be strong. A fragrance can cause an allergic reaction or offend the interviewer(s). When in doubt, do not wear cologne.