Before launching any marketing campaign, it's important to determine your primary video goal. This could be to increase brand awareness, engagement, or even conversions for a free trial. It's crucial to pick out just one or two goals for each video. When you define more than that, your video will seem unfocused, making it difficult for viewers to determine what they should do next.
Opinions vary greatly among sound engineers on the best method and equipment for recording audio with a DSLR. You've likely seen many videos that use a lavalier microphone — the small piece that clips below the collar of the talent's shirt. Lavaliers come in both wired and wireless options. However, lavaliers can be a bit obtrusive both for the talent (who has to have a wire threaded down his or her shirt) and for the viewer (who has to see a microphone for the whole video).
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.