Many of us (especially older developers) have been in this game a long time. We remember the days before the internet...yes, there were a lot of computers then too. As everyone grows in their career, you think back to what you have learned and from where.
If you could send a letter (or email) to your past self, what advice would you give about your career? What to focus on? What work patterns (not design patterns) or ways of attacking problems would you gift to your past self?