When I showed up for my first play audition (as a favor to the playwright), I was asked for my resume. "You mean with my chemistry internships and stuff?" I replied, confused.
I was one year out of MIT and totally clueless about what an acting resume was, let alone what a headshot should look like. Honest to God, this is what I brought to my next audition:
That is a glamour shot from Taiwan, my friends! Hugging a plastic pole - that spells professionalism, right?
Fast forward many, many years of experience later -
We had an industry guest at my acting class last night and I snuck glances at some of my classmates' acting headshots/resumes. I was very surprised to see bad headshots that didn't look like the actors, resumes formatted weirdly, headshots that weren't 8x10 size, etc. It was easy to separate the amateurs from the professionals. Or at least, the amateur-looking headshot/resumes from the professional-looking ones.
What impression does your headshot/resume make? Because you can be the greatest actor in the world and still make a bad first impression with your headshot/resume before you even open your mouth.
So take the time to get it right. Search "How to Create an Acting Resume" online for advice and follow the steps. Get together with fellow actors and critique each other's headshots. Ask every actor you meet to see their resume and notice how they list their credits.
I'll even show you mine to get started: