Any professional actor who has been in the industry for some years has had a headshot photo session or few. However, I've come to find that there are many newcomers and even some more experienced actors who are still a bit uncertain about some good steps to take to prepare.
Photographers may suggest different approaches based on what they specialize in or based on what your photoshoot is aiming to accomplish. I pulled an old article from Backstage with some tips that I think effectively cover how best to prep for your headshot session. Check out the link below.
Headshot Photoshoot Prep