Shhhhh! Background noises can easily ruin the day if you're not careful about the environment, or if your setup is not properly balanced. Here's a review of one post-production solution that will help you easily remove unwanted audio noise and reverb from video clips.
Speaking of video clips, here's a quick but well-written -- and relatively thorough -- guide to DIY video marketing. It has examples you can copy from while establishing your own strategy to conquer this crowded market.