I dropped out, but was able to come back later.
This is what I did: I kept track, throughout the day, of every little thing I did that might be considered good--everything that worked me a little bit closer to my goals. Since my social skills were so bad that I was terrified of talking at all, I counted things like greeting people I knew or talking for a couple seconds with a cashier; in other words, I tried to keep a realistic eye of progress. Whatever was hard counted.
Then, at the end of the day, I folded a paper crane for each act. My deal with myself was that this last thousand good acts was the timer before I'd be able to kill myself, but I barely made a dent before I'd filled an entire two drawers of my school desk and covered the surface with a bunch of paper cranes, and ended up feeling kind of proud the moment I stopped going through my day on autopilot. I also kept a notebook in which I wrote three things about myself that I liked every day. Often, it was just stupid, petty stuff. "I have great ankles." "I didn't emotionally manipulate x today." "I'm alive right now."
JoshuaFH also told me to smile at myself in the mirror at the beginning and the end of the day, and oddly enough, that worked, too. So did keeping a diary to reflect on everything that happened (mostly bad, but there was some good).
For me, it wasn't about sticking to one thing for a long time. I basically alternated between four easy things, and did them whenever I remembered. Slowly, things really changed.