volume level

I've read it's best to capture audio around -12dB. However, when I do this the volume seems a little low for my taste. So I got in the habit of setting my audio at higher rate. However, someone told me that this isn't the best practice and the best practice is to capture audio at around -12dB...

As a reviewer, one of the key parts in my videos is the audio commentary. It has to be clean and consistent, in order to be easily understandable. However I've been having a problem with the volume levels. They are inconsistent. A sentence can have some words or syllables with a very high volume...