Hair
Hair should be clean, neat & should be in an easily managed style. If you colour your hair, ensure that it's freshly done for the interview.
Make-Up
Make-up should be subtle. Wearing too much make-up is a real no-no. Try to keep it as natural looking as possible.
Jewellery
Minimal is the way to go. A pair of earrings, a watch, a necklace & maybe a bracelet is the most you should wear. In any case, jewellery should be classic & simple in design.
Blouse
Go for a clean white blouse. You can't go wrong with white.
Jacket
Whilst not imperative, a jacket is always a good interviews, especially in colder temperatures. Choose a jacket that is clean, pressed and well fitting. Colours to go for include grey, charcoal & navy.
Nails
If you want to wear nail polish, go ahead, but avoid wearing an extremely bold colour. Also, ensure that your nails aren't chipped. It looks unpolished & unprofessional.
Skirt/Trousers
Either is fine, but if you do choose a skirt, choose one that's well fitted & knee length. Whichever you choose, make sure they are the same colour as your jacket.
Tights
If you choose to wear tights, go for dark tights & ensure that they aren't laddered!
Shoes
Shoes should be clean, polished & should match your attire. Don't be afraid to wear heels, just avoid going too high.