Make your location prominent. They won't be looking for you by name, they'll be looking for someone in your area. Put the city or state you cover in a prominent location. They are organized by state, and provide a handy reference. Many of the larger state associations have listings like this in their magazines as well.
People tend to stay with what they know.
If you want to encourage attorneys to change to using your services rather than someone else's, you need to give them some incentive to do so. Incentives aren't necessarily monetary. The cost of a transcript is passed through to their client, anyway, so a discount on their first transcript probably won't get them that excited. Instead, combine the marketing principles of informing clients of your services and providing incentives. This not only encourages them to give you a try, but reminds them that the service is available.