This is my standard MO for learning big new ideas. Say for example I want to use MVC for the first time. Once I think I understand the general idea, I will build my own. I might peak at Rails or Struts or whatever to see how they solve something, but in general I just go my own way. Once I have something to approximately proof of concept level, I feel ready to go out and evaluate existing options with a pretty high level of confidence in my conclusions.