Just surround yourself with good people/players. FC, friends from real life, and take advice that's given to you. There is always someone happy enough to show you how to play, or tell you what you do wrong in a kind way. I always give instructions when I see a new player, and if they do something stupid I will let them know how they could fix it. If they are stubborn enough to not listen, then they are harming themselves.

Likewise, the person who is mean while communicating about errors of others is hurting themselves the most by acting like a moron.