Unlike the prototype, super-elevation is not needed on our models, but it does make some track look good. You have to be careful when you start the super-el so it not an abrupt start, which can cause the trains to derail. The best method I've seen to start the super-el, is to securely glue down a strip of cardboard, on the outside of the curve, at least 1/8 the length of the curve. The cardboard needs to be the thickness that the super-el will be. When dry, sand the cardboard down from the high end until it feathers out to nothing at the end where you want the super-el to start.
I've also seen layers of tape used, but it may not be as smooth as the cardboard. A mistake that many modelers make is they make the super-el too steep. Its very easy to do this. I was taught that anything thicker than a paper match from a book of matches is too much. Since I learned this for use with HO, I would think 1/2 this thickness would be good for N scale.