I don't' have a tablet yet so can't help you there. I probably do a lot of stuff the hard way just because I am coming from an old school background and am fairly new to digital painting.
Here is a screenshot of how I have mine set up. (the image is just a little experiment I was working on for a new style of mountains)
I also added on: http://code.google.com/p/gps-gimp-paint-studio/
I have created a folder of brushes I have created for different things as well.
That's about it, I don't think I have any speed tricks.