If you want to draw cool cartoon characters that aren't just precise copies of an online tutorial, pick up a pencil and draw a person from life. It'll suck, but do it in earnest a few dozen times, and pretty soon you'll have an idea of how to distort reality into cartoons.

These tutorials are the end result of a lot of invisible rule-breaking (a nose looks like x, a hand looks like y, etc.). You can't break these rules intelligently unless you know what they are. And since everyone has access to reality and a pencil, there's nothing preventing anyone from discovering the rules.