If I could restart this year, I'd choose different subjects. I'd really think about what I wanted to do when I went to University and do A Levels that were more related to that field - I want to do a tech degree now, but thought I wanted to do a humanities degree when starting college.
I'd also be a bit more open and I'd attend college more than I did (something like 60% attendance), although I do have reasons why I couldn't go.