When you consider your clothing choices for you headshot session you need to remember a few key things. By definition a headshot is about your face. There should be no things in the image that distract the viewer from your face. So, with that in mind:

Avoid loud print and frills and choose solid colours.
The fit of your clothing is important, baggy or excessively tight clothing won’t bring out your best. According to headshot photographer Nina Parker “well fitting clothing makes you look neat and polished.
For Women
Bring four or more of your best fitting professional dresses and tops and bring a few jackets that go with these tops or dresses if you want that desired look.
Bring a top or dress that matches your eye colour if possible.
For Men
Bring three or more of your best fitting professional shirts with crisp collars and collars stays. They should be pressed and one solid colour.
Bring ties that are complimentary to your shirts and they should simple without bold patterns.

Consider bringing clothing for a more casual look i.e. Facebook image.
Bring any leather jackets you own.
Bring any clothing you enjoy wearing!