I wish I had forced myself to spend more time on campus rather than going back home as often as I did. I would have given myself less grief if I treated school like a 9-5 job. I could have gotten more work done while on campus which would have given me more time for socializing, fun, and sleep.
I also wish I had chosen something more substantial for my senior project. I basically threw together some things I was interested in working on into one system, purely for the sake of learning and with no real concept guiding the project. The result wasn't really impressive, nor did it solve any problem. I certainly learned a lot from my senior project, but I would rather have had a project worth showing off to people, or a product with which I could potentially have started an enterprise.