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).
One of the most important aspects of post-production is editing your video footage. Of course, that involves cutting and splicing together your b-roll, interviews, and lifestyle footage to create your story. But it also involves adjusting other visual elements, like white balance, color, and clarity, to accurately represent the story you want to relate. These edits will create the entire look and feel of your video, which highly affects its branding. After all, when you think of an Apple store, you don’t think of dim, romantic lighting, so make sure your color edits reflect your creative vision.