I would personally wear a business skirt and skirt. Something sleek and tidy.
Probably a black or grey skirt and a white shirt, maybe a striped shirt but leave it pretty plain and simple. And a pair of heels, not too high but not too low.
And my hair always in a sleek low ponytail.

You could make it a little more fashinonable if you wanted but I found that is the best outfit. It shows you are serious, made an effort to wear something nice without looking like you are trying to be in a magazine iykwim.