Although I am a firm believer that there are hardly any fashion rules left, there are some in corporate America. I wear many hats...when I am teaching I will dress appropriately and for Styling Session a completely different way. Every work place has a different dress code. But there are certain tips that you can use for every company.
Casual Friday: Casual Friday does not mean sloppy! Look cute but still look professional.
Jewelry: Accessories are key to creating a unique and put together look. Keep the jewelry appropriate and tasteful.
Grooming: Always make sure your look polished and professional. It is important to make a good first impression and keep that impression up. Don't have wrinkles in your clothes and always have well groomed hair, nails, and toes.
Hair: There is a such thing as letting your hair grow but that doesn't mean you should ignore trims from time to time!
Makeup: Too much makeup is never a good thing. Be natural in appearance.
Hats: Hats are a big no no. They are not appropriate in the workplace, except for head covers that are required for religious purposes.
Shoes: If you are allowed to wear sandals or any kind of open toed shoes, make sure your toes are properly groomed. Some quality nail polish time never hurt anyone.
If you are in a fashion business there will be more liberties you can take. It is all about self expression rather than a corporation where they want everyone to look the same. Always dress for the position you aspire to be in. If you are interviewing, you should dress for the job you are going for. You may even want to dress for the next position up. If you are an intern, dress like the assistant.
Here are some thing you should avoid in any workplace just to be safe: denim, logo shirts, sneakers, hats, torn clothing and flip flops.