That's kind of a broad question, and there's been a lot of marketing discussion on this Board before. What kind of show are you selling?
If you're looking for corporate gigs, I'd suggest investing in Oz Pearman's second "Penguin Live" lecture. (I didn't see the first lecture, though it was apparently more effect and technique oriented.) But I did see the second lecture, which focused heavily on corporate gig marketing.
You can either download it or stream it. (I prefer the download because it's easier to stop, start, and find your place again.) At 3-1/2 hours, you'd likely want to watch this in at least two sittings. http://www.penguinmagic.com/p/2697#reviews