Remember, you may need more than one! The headshot you use needs to be geared toward the parts you want. A bit toothy grin may not work if you are auditioning for a Shakespearian tragedy.
Here are some links to help you get a good headshot!
You have your headshot and resume. Now you need to find an audition.
Google is your friend for this kind of search. Use keywords for the type of search you want, for example you might search the following. Be creative!
Contact local theatre companies directly like the Merced Playhouse, Good Company Players in Fresno, or Prospect Theater Project in Modesto. Don't be afraid to make a phone call to local theatres, they are always looking for new talent
Auditions can be hard but this is where you get your chance to shine! Think of it like a first date, you are both deciding if a relationship is worth pursuing.