I think what I would say to my younger self, and probably to younger, just starting-out writers is that a lot of times you're just afraid to put yourself out there, and it's uncomfortable because it's working up the courage to do something, to push yourself to do those things.
No matter how vital experience might be while you lived it, no sooner was it ended and dead than it became as lifeless as the piles of dry dust in a school history book.