The key to appropriate interview attire is to keep things simple. Do not wear anything that may distract the interviewer. Your appearance should be professional and tasteful, yet completely unremarkable.
Hair should be short or tied back.
Invest in a solid-color, conservative suit with coordinated blouse in a pastel or other simple color. Wool or a wool blend is a good choice. A skirt or pantsuit is fine—choose something you're comfortable in. If you wear a skirt, it should be knee-length.
Wear a good pair of polished dress shoes with a closed toe and back. They should have a two-inch heel at most.
Wear a belt that is in good shape and free of scratches.
Wear tan or light hosiery (pack an extra pair just in case you have a run or snag).
Keep jewelry simple and classic; no dangly earrings or multiple necklaces or bracelets. Pick one statement piece of jewelry.
Wear a conservative-style wristwatch.
Wear contact lenses rather than glasses. If you only have eyeglasses, wear a conservative design.
Keep makeup natural looking and conservative in application and color.
Keep nails neatly trimmed and simple. Avoid wild nail polish or extremely long nails.
Avoid bringing a purse or handbag; try to stick to carrying only a portfolio.
Be conservative with perfume. Don't have an overwhelming scent.