In general, just wear what you would wear normally. Large and colourful headwear and accessories may distract from your photograph if you are looking for a purely businesslike presentation. On the other hand, if colourful accessories are part of your personal ‘brand’ you should definitely wear them!
Similarly, makeup is a personal choice. There is sometimes a temptation to wear a little more than usual, as you might for a special occasion; I would caution against this, simply because when you view your image later you may feel that you appear ‘over-dressed’. Don’t worry too much though, our lighting will be set up to show you at your best and it is relatively straightforward to tone make-up up or down a little in the post production process.