There is something about reading a detail-abounding book that makes you want to go and make all those neat gizmos and gadgets and whatnot. Also, watching the movies for the millionth time lets you notice the little prop details.

I've already posted instructions on a light-up wand. But for a more movie-accurate, lighter, and much easier wand, I suggest this method.

First, take a sheet of computer paper and lightly coat with Elmer's glue. Roll the paper diagonally as tightly as you can. Allow to dry.
Next, trim the ends with scissors. For wands like Hermione's, that have carved detail,  use a glue gun to glue on the design.
Then, paint with acryclic paints. If you glued a design, you may or may not want to paint the design in a lighter/darker shade.