It would be interesting to hear from someone who does make money from YouTube. I know it is related to things like the number of views, likes and favourited - presumably whoever puts the adverts on pays according to the audience for any video so it will vary ... but I don't know that for fact. There are videos on YouTube which claim to explain it all :)

There are adverts on/to the right of 4 of my videos because they may include content that is owned or administered by these entities: Entity: Music Publishing Rights Collecting Society Content Type: Musical Composition and of course I didn't get a choice about those and none of the money comes to me. However those adverts are a small price to pay for being able to put up songs from LPs that are rare. I just find it enjoyable making the videos and sharing with people who appreciate them.