I usually draw on the oekaki board. I like it a lot, but one of the limiting factors with oekaki is that the maximum canvas size is rather small. YOu can work on much larger pictures in Photoshop Elements, or other software like that.
To try to get around that, I've been experimenting with enhancing some of the pictures that I've done using vector traces and Inkscape.
So far, the results seem promising. By request, I whipped up a tutorial.
Check it out, if you're interested.
http://chromamancer.deviantart.com/art/ ... -125350261