This is so obvious as to be comical to a 'serious' audience, but:
I am writing down the exposure and apertures I’m using. Bracketing more. Going back and adding the exposure/aperture data to files when I scan the picture.
Result: knowing more about how to best capture a certain kind of light. Damn, I wish I hadn't lost the receipt on which I wrote down the exposure/aperture for this one! I'm guessing f/11.