Rule - Tighten Everything, Rinse, and Repeat
I try not to make a habit of detailing everything I do in a day, specifically to point out my mistakes, but if you do enjoy cycling, heed this warning. Tighten your shit. After you think you've tightened everything, give your bicycle another once over. No one wants to be breaking the sound barrier down a hill only to have their handlebars shift significantly out of position. That is not part of a healthy lifestyle.
(I'm fine by the way, this is not a posthumous blog entry, although it will be archived in the event I forget this rule.)