Thanks for the responses so far. I think the "wear something uncomfortable and annoying" (like a big clunky ring) idea is the most helpful so far. The problem is not self-control, it's just *remembering* to check myself (and realizing whether what I'm doing might constitute complaining or bragging). When I was learning the basic social skills of eye contact, monitoring how long I've been taking about the same topic, whether it's time to let the other person speak, whether the other person is interested, etc., I had someone helping me who constantly reminded me and pointed out when I made a mistake. This time I'm on my own. I guess I can ask my friends to point out to me when I'm doing this stuff, but I don't want to put the responsibility on them and I spend more time at work than with my friends anyway.
On a side note, I think it's kind of cool that there are enough players of DF on the autistic spectrum that I don't have to explain in detail what I've gone through learning to act normal. Something about this game...
In response to other comments: I went through a long period of time (ah, those teenage years... aren't we all embarrassed about them when they're over...) when I thought the world was just full of jerks and I shouldn't have to change for them. Then when I found out I had asperger syndrome, I finally realized that I'm the one acting inappropriately, not them, and if I ever wanted to be a part of society, I had to learn the rules. These days I'm 25, living on my own in a foreign country, and I have plenty of friends, but I'm still finding myself lonely and left out a lot because people just don't want to spend too much time around someone annoying. I think if I can overcome a few more hurdles, I'll be all set. I'll always be a bit odd, but that's ok by me and the excellent friends I have.
The problem is also definitely not that I'm not busy enough. I get up every morning at 6:30 to get ready for work, spend the whole day traveling around the city teaching English lessons with a few short breaks for planning lessons and eating (and writing quick messages on the forum), and don't get home til at least 7:30 pm most days. I barely have time to think and I'm exhausted each day when I get home, then have to make dinner and prepare the next day's lessons before bed (with the occasional hour or two dedicated to some computer games). The constant talking is just part of my personality. Even as I'm running from metro to tram to bus and back again, I'm muttering to myself constantly, and I even catch myself sharing too much with my students, who probably have no interest in my personal life whatsoever. And my poor flatmate (who puts up with this very well and only just pointed it out one night when we were both very drunk) has to listen to me every day before each lesson going "I don't WANNA go teach! I'm *tired* and I wanna go to *bed*." and after each lesson going "That lesson was so great! My students love me so much! I am the greatest teacher!"
And now it's back to work I go... One more lesson and then I'm free!!!