Relocate to the East or West Coast, based on your needs and goals. If you would like to pursue theater as a professional actor, the logical choice would be to relocate to New York City. Once there find a "day job" to support yourself. Pick up a Backstage News paper. Backstage lists current castings for student films, theater products, low budget commercials and modeling work. Submit to your heads hot to everything you may be right for and start building your resume.
Relocate to Los Angeles if you are more interested in film and television work. Backstage is also published in Los Angeles and a great source for finding acting jobs on the West Coast.
Stay local if you plan to pursue acting as a hobby or are planning to test the waters before making the big leap. Opportunity abounds in many smaller cities. Check your local newspaper for theater performances and contact the productions to inquire about auditions.
Invest in quality head shots. These are an actors calling card and the item that will get you into the audition. Headshots are photos of the actors upper torso. They are tight framed photos to showcase the face of the actors for casting purposes. Local photographers vary in quality and pricing; select carefully. For Los Angeles and New York actors there are a number of photographers to choose from. Many advertise in Backstage. Call photographers to make an appointment to see "their book". Prices for head shots in larger cities range from $500 to $1000 dollars for a sitting with multiple wardrobe changes. Most include hair and makeup styling but not the photos themselves. When thinking of your head shot, remember that it will represent you, and how you want to be cast. If you are wanting to be a character actor do not do a "glam" photo session, instead incorporate elements into your head shot that you would likely be cast as. If you are an older gentleman perhaps you would be cast as an attorney; don a pair of reading glasses in your head shots and perhaps choose a nice suit as your wardrobe.
Compose a resume. This fact-based resume accompanies your headshot. Information should include your relevant acting experience and your height, weight, hair color and eye color. Have these printed and cut to an 8 by 10 size. Staple copies of your resume to the back of your head shots to send out.
Pound the pavement for work. Work begets work, the more you can be seen the better.
Establish yourself as a professional by joining one or all of the professional acting unions. SAG represents television and film actors, AFTRA represents radio and AEA represents professional actors for the stage. Once you join these unions, list them on the back of your resume. Your pay scale will dramatically increase by belonging to these unions as well as your stature in the acting community.