The face isn't bad at all. I don't really like how he has a glow around his head, I think being crisp is alot better. Speaking of which, the hat is a bit choppy.
As for the neck, google is your friend. Use it.
Overall, you're on a somewhat good path to bettering yourself as an artist. Just read your feedback, and take the time to actually implement it. Most artists take a multitude of hours to complete their works, and as the saying goes, Rome wasn't built in a day, so don't feel disheartened if you end up spending quite a few hours and don't have all that much to show for it. It's quite common.