Answer.......................Everything.
BUT...........In my first year at "Gramar School" (listen to me!)........I was put into a metalwork class. In my ignorance I wanted woodwork, but knowing what I know now.......Phew! we had a fully equipped workshop with lathes and bench drills, and grinders, and oxy acetylene....oh my god it was heaven.
BUT, I didn't see the obvious. The Headmaster was ex RAF and built a plane which eventually he flew off the school fields, which were huge....................
There was also an LNER scale model pacific locomotive which was unpainted, and about four feet long. I never asked who built it. So there, I should have capitalised on metalwork, but couldn't wait to stop doing it.
Everything else I took the easy route, so no swotting, all seat of the pants. Knowing what I know now I should have worked a lot harder.