Okay seriously,
UNLESS you are interviewing at Easyland, where things are a little less formal, WEAR A SUIT! I think white shirts are good, clean and crisp but you dont have to. Pale blue is calming. Get someone's opinion for a brand new tie that complements your shirt AND suit combination.
Shoes, black, clean and well polished.
Hair, neat tidy Perhpas get back sides and neck shave done three days before.
Watch should be discrete and same for other jewellery but if you are a lad DON'T wear ear rings to an interview.
GOOD LUCK!