All what you have heard. All what you have tried. All what you have seen.
Tell us WW about it.
Lightweight/Aero/Fit/Nutrition/Comfort/technique/Unwritten Rules/Tech/Anything else that you know works for you, tell us. We will read.
The main aim is to have a thread, where someone just reading from page one to page X might find THAT one tip/advice, which will transform his/her cycling life. If it's not applicable to them, they skip it. But if it's important to them, you might have just helped someone achieve their most comfortable/aero/lightweight goal that would really benefit them.
So go on, write your advice.
Rules:
All advices in bullet form.
1.
2.
3.
etc.
No comments on someone's else's advice, however blasphemous it may be. Please refrain from stupid advice like trying a triathlon or something. (They don't wear socks, Jeez

Go!