Here is a list of important things to remember:

Look like your headshot at auditions
Not too much or too little make-up
No Glasses in your primary shot
Not too much cleavage
Not too Stiff
No duck lips
Real Smiles
Show Teeth
Best image is not always your favorite image
No brick walls
No hipster glasses
Don’t look pensive
Don’t look like everyone else
Show off your talents