Well, the problem with say

Well, the problem with saying you want your audio to be like most YouTube videos is what you hear from Youtube is based on the viewer’s volume level, not the videos audio levels. A video on YouTube could have very low audio levels, but you wouldn’t know it if you just turn the volume up. Or the audio levels could be too high, and the viewer’s volume could be low.

You have to look at your audio meters in your editing program. Audio should be around -12dB and not peek above -6dB. If the audio meters in iMovie aren’t in measurements of dB, but instead a percent, then you need a new editing program. Saying your audio is at 200% doesn’t mean anything. 200% of what?