I watched the Zoe Fitness video and I think the lighting isn't too bad, but your audio could be better. I would suggest perhaps one of two things. Either put a lapel mic on your subject, which doesn't have to be super expensive or get a mic stand and hang a boom mic over the subject, zoom that camera in a bit closer and put the mic just out of the top of the frame. It will help your audio be clearer, and reduce that echo a bit. Those a just a couple of initial tips.
RE: DTube Audio Quick Tips to Up Your Game