Like RCFreak said, just look at how the pre-made ones are designed.
Once you get the hang of it, it's awsome to be able to do whatever you can think up, at whatever speed and angle you wish.
Only tip I can offer is to use less of those edit points (vertexes) to make it smoother.
One for the bottom of a drop, one at the top of the next hill, and so on. Unfortunatly u can't be that stingy with curves if u need them even, though
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-Troy
EHT (Extended Hangtime) Survivor - Cbuzz Con '03
Chance Rides - Leave it to Chance