If you have a business telephone, you get a free listing in the yellow pages. Usually all you get are calls from someone looking for work or trying to sell you something. You might get lucky and actually get a contract. Direct mailing really makes you determine your market. You can purchase lists of potential clients, research company names at the library, or use company names from the yellow pages.
Direct mailing is costly and has a moderate to low effectiveness.
Give a presentation on how to do something that relates to a popular topic. If done right, a good presentation shows your organizational skills and how you relate to your audience. Besides being a member of STC, join other professional organizations that relate to where your clients might look for a contact. Remember, get involved so members get to know you by giving a presentation or a workshop. However, pace yourself.