When I first released newton2, I created a series of tutorials that explained some of the basics of designing specific elements. Since then, I've been adding to the series at the rate of about one tutorial a month, and I'll probably continue that trend as long as there is sufficient demand for more.
I think I linked to these somewhere in the long newton thread, but it's probably best to separate them out so they're easier to find. I'll try and update this list as I add more.
IMHO, the first (creating lifts, brakes) and sixth (saving an element) are the most important, since it covers quite a bit of new functionality even if you are familiar with force-based design.
tutorial 1: stations, lift hills, and brake runs
tutorial 2: loops
tutorial 3: zero-g rolls
tutorial 4: Immelmann and dive loops
tutorial 5: cobra rolls
tutorial 6: saving an element
tutorial 7: camel backs and Stengel Dives
tutorial 8: flat turns
tutorial 9: corkscrews
Now, these are meant to be patterns for integrating similar elements into your layouts, so be aware you'll have to adapt them to meet your needs. Hopefully, they'll be enough to teach you the principles involved, and that by watching them you'll develop a better intuition in creating new elements.
What comes next is up to you (...and me, too [8D]).