I believe that sound is almost more important than the visual. That might seem ridiculous but maybe it's because I have a high regard for sound in general. I think radio programmes are wonderful because they describe stories so powerfully using only sound. Do not underestimate the importance of sound in your videos. Get good clean levels. Take your time making sure you're recording good audio. Always use headphones. Plan for sound effects. Look out for distortion or wind noise.
Here is a video that explains this all a bit more in depth. Just a few tips to remember.