Look Who's Talking
Sometimes it can be very useful if you think about who says something.
Is it someone with a huge knowledge about what he is talking? Does he have any proofs of competence? Can he give reasons for his opinion? Or is it just someone with too much time and self-confidence?
So for example if somebody criticises or praises you – just think if he is competent of judging you or not.
And if he is not, go and search someone who knows what he is talking about.
And if you find someone competent, snap the chance and listen carefully.