For a long time I kept good notes, but I guess I getting lazy in my old age. (I'm a 'general' woodworker and not just a scroller.) And even though I'm mostly a hobbyist, I tried to track everything:
what was made
Where the plans/pattern came from
what, if any, modifications I made to the plans/pattern
they type of wood(s). If I'm following plans I'd list any substitutions or stock that I choose to employ.
where I got the stock
careful notes on finishing, , colors, number of coats, blah, blah
who the project is made for, if not us
problems I encountered and what I did to resolve them
and how I install the project (for cabinets, shelving, special molding - especially if it's in someone else's house)
time
and charges if it was a custom job for cash or trade
and if a project had outside cost, other than the usual stuff, say glass for a cabinet door. Who I got it from and what they charged.
At the back I keep a list of odd (rarely used tools/jigs) and where I stashed them. An entry might read: Small cross cut sled: west wall of garage near ceiling.
I'm going to try and get back to that, it's really good to have a record.