One of the best ways to improve the look of your video is to include b-roll. B-roll is the supplementary footage included as a cutaway. This might include shots of a customer service rep talking on a phone, a designer editing your website, visuals of your office, or even screenshots of your product. The key with b-roll is to make sure each and every piece enhances the story.
Professional cameras, like DSLRs, give you fine control over the manual settings of shooting video and allow you to achieve the shallow depth of field (background out of focus) that people rave about. While they're primarily used for photography, DSLRs are incredibly small, work great in low light situations, and pair with a wide range of lenses — making them perfect for video. However, DSLRs do require some training (and additional purchases) of lenses.