While the concept of CQRS is fairly simple to explain my experience is that it takes some time to master. The reason is that there are a lot of things to unlearn if you're used to developing your vanilla application.
Browsing through the August issue of MSDN Magazine this article on CQRS reminded me of something I read a while back that I had to dig up. In this other article four different types of CQRS are defined (where one is not CQRS). The beauty of that article is that it by defining the different types of CQRS it is really explaining how CQRS should be implemented.
That is you don't have to strive for type three if your requirements don't need it but it also illustrates a clear migration path from type one, via type two to type three. And I think that is good.