Also, just make sure what needs to be straight is straight: Lifts, breaks, LIM's, etc. And build rides your own way. Make them realistic for the style. That's all I can really think of. The NL articles are also helpful so check those out.
http://www.coastercrazy.com/articles/
Also, really be sure to take your time on a coaster. One built in a few hours will not be as good as one that had more time put into it.