Beyond the guestbook call to action...

This article from ClickZ covers some good advise beyond the typical search optimization, but suggesting you think like your client. The author does mention 'vertical' lead sources such as Thomas Register, too.

Things get sophisticated, though: When measuring, managing, and optimizing a campaign, you may want to set blended objectives that go beyond a simple "contact us" lead form or a phone call. In other words, for a visitor not ready to contact you, can you create another objective for them to achieve on your site that will help move the sales process forward? A download or a demo, for example?

B2B Search Best Practices