Eating your own cooking.
This is a pretty big problem today. There's just so many stupid people giving stupid advice, and they just so happen to a have a really loud voice. Which comes down to the question, have they eaten their own cooking? To take this literally, would someone ever trust a chef that claims his new pasta sauce is amazing, when he himself has never tasted it? Of course not.
The best way to gain reliable information is to directly go to the people who experience and have lived what they advise. The phrase "Eating you own Cooking" comes from Nassim Taleb's book Antifragile which has lead me to experience peoples advice in this new perspective. Which is honestly breath taking, as you begin to realize just how full of s*** some people can be.
This is why wisdom is often associated with old people. Because they've experienced what they've learned first hand.
Which is why job experience is so valuable to employers. Because they know that you've experienced it and lived it. So unfortunately we spend most of our childhood learning but not experiencing. Don't worry though, there's a solution to this and that's co-op schools. A good example is the University of Waterloo.
The best way to go about taking advice and giving it, is to trust the advice from people who've experienced it first hand. While being skeptical of the ones who haven't. The tricky thing about this, is finding out if the person really did live that experience.
Have fun finding the wise ones!