I wouldn't call myself overly coordinated, but I've managed to learn how to mountain bike over the last year. That's not to say that I've world class at this point, but I think I handle the trails I ride fairly well. I began by taking a day-long skills clinic that is offered locally every summer. I can't stress enough how helpful that was. I don't think I could have picked it up nearly as quickly without that. So, if you can find one in your area, I'd highly recommend it. There are books, DVDs and online tutorials/videos available, too, but nothing beats live instruction from a certified instructor.
As for shifting, it could be that you were on too big of a cog in the back when you shifted to your little ring (they're called crank rings in the back and cogs in the back). Try shifting to the little ring from the middle of your rear cassette. But the general quality of your drivetrain and whether it's well tuned can play a roll in dropping a chain as well.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher