This tip comes from these guys, they are pretty spot on. Only two things I would change is that audio is worth the investment. You will be better off investing less in camera gear and using that extra money for audio. Your production will suffer otherwise. Other thing is to buy a wireless lav such as the rode link. $400, but you can mount the receiver on a hot shoe mount and it doesn’t matter how close or far away you are, you can have clean audio. Also, the audio goes directly into the mic so you won’t have to sync in post.
8. Where’s your mic? – Many amateur videographers or budget filmmakers don’t have the luxury of having an audio tech to hold a boom mic for them. Often the case in budget filmmaking, you are relying on the mic on top of your camera for sound. If that is the case, you will need to always be conscious of where that mic is relative to the sound you are trying to capture. If someone is talking, you will need to have the camera very close to that person, otherwise it will be annoying for the viewer to strain to hear what they are saying. The reality is that getting good sound will often dictate your shot.