General Tips for Selecting an Advertising Medium
If your target audience isn't widely based, choose 2 or 3 primary advertising vehicles … ones that are affordable and in which you can dominate. Don't rely only on one form of communication; choose media that complement each other to ensure that your prospects receive your message.

Choose methods according to cost, targeting and response. A campaign can be broken down into costs per thousand. If you're using direct response advertising, evaluate your success using a cost per sale formula. Expenses include creative (cost of design), production (producing or printing ads), and placement (TV, radio, advertisements, mail list purchase and postage).

The more targeted the media, the higher the cost. With a more targeted media, you should expect a higher response rate resulting in a cost per response being lower than less expensive vehicles. Companies that sell advertising can provide you with information about their market which should aid you in making the right choice.