Building a professional wardrobe for women is not as difficult as it seems. Start with a good basic three piece suit: jacket, pants and skirt in a dark blue or gray tones. These three pieces can then be built upon. They can be dressed down with sweaters, blouses and accessories to accommodate a more relaxed work environment, but still be dressed up when the situation calls for it.
Have a good pair of black pumps in your closet. A toe and heel in shoe is the most professional, and black goes with everything. Keep the heel height to 1-2 inches. If it is too high, it can be perceived as sexy.
Keep accessories to a minimum, but good quality. No oversized earrings or noisy bracelets for an interview. They become too distracting. Carry a well-kept purse that is not overstuffed. A purse that will handle your resume and other items needed for an interview will allow you to carry only one bag, which is best.
Wear a little makeup, minimal or no perfume and a hairstyle that is well-maintained and out of your eyes. You don't want to be fussy with your hair during an interview.
Happy job hunting.