Well, you don't "Get Better" by sitting around grinning and bearing..... Route building for Trainz is actually rediculously easy compared to most forms of content creation for pretty much any other game out there.... In my experience it has alot more to do with generating a working knowledge of the available assets to work with (Of which I know there to be a minimum of 330,000, though I'm maybe familiar with less then 5,000, though I have almost 60,000 downloaded), then anything else. generating a working knowledge on how to use splines and accomplish certain effects in the game helps, but those are the kinds of things you're only going to really get by learning yourself, and they're meant to come with experience anyway.
Try it sometime. Start smaller then the route of the "Surfliner" (Quotations and an extra R thrown in for a certain someone), because you'll probably find that overwhelming, but just start by throwing some assets down and seeing how easy it is to make a route....
Falcus