My first suggestion would be to ask the investor that you would be birddogging for. Also, take the time to read articles here, and books from the library on marketing to get people to call you. There is a ton of free info on this subject floating around the web.
Also, kind in mind that a birddog's job is merely to locate potential deals for investors. They do not negotiate the deal or discuss terms. That's the investor's job. The birddog is just supposed to locate the property, and find out IF the owners are open to the idea of a disounted cash sale, lease-option, etc. and IF they want the investor to call them to discuss their options.
hope it helps,
Roger