I'm someone who can provide an intellectual framework, but I can't tell people who are trying to sell Product X how to do that because I don't know, and I would be faking it if I attempted to step into that role.
A lot of people change for good. Some people just fall off. Just trying to progress in anything, no matter what you're doing, I feel like any progression you make... some people aren't gonna be around you that were around you.
My writing model is my mother, who is a writer as well. She always valued clarity and simplicity above all else. If someone doesn't understand what you're writing, then everything else you do is superfluous. Irrelevant. If any thoughtful, curious reader finds what I do impenetrable, I've failed.
We sometimes think of being good at mathematics as an innate ability. You either have "it" or you don't. But to Schoenfeld, it's not so much ability as attitude. You master mathematics if you are willing to try.
That fundamentally undermines your ability to access the best part of your instincts. So my advice to those people would be stop thinking and introspecting so much and do a little more acting.