One thing that is vidal to your coaster is banking. The most realistic banking is when you make sure your track is flat no matter what. By that I mean, if you doing something like an over-banked turn, you make it so it turns over-banked but looks flat at top of the element from the side view. Example, you don't want to make an over-banked turn go 100 degrees unless it's so low enough that it would look flat from the side view. I've seen improper banking so many times you would'nt believe me! This is my view on banking and I do believe it is correct but you DON'T have to listen to me. This was just my thoughts on banking caus' I notice it on real coasters.
-Hope this was helpful.