A good skincare and hair routine is good to have anyway but can really do wonders for the final images. After all the whole idea of a headshot is to show your face.
Dress for the job you want, or that you already have. A polished look that matches what you do will have a present you in the best way.
Where do you feel the most alive? Trusting your photographer and getting yourself into the best headspace will produce amazing results.