New2, if you haven't set up an Adwords account, do so and you can get familiar with the keyword and traffic estimator tools. It's especially helpful to see how people in your area search. "lawn" vs "yard" is a good example of this.
Assuming you have analytics software on your web site (you do have a site, I hope?), take a look at how people are arriving at your site and that will help you refine your campaigns as well.
a guy who knows both the lawn business and web strategy