If you aren't using UML, you probably don't need to read this article.

Also, it features one of my favorite nits about examples - it uses a non-technical example (seminar registration and then actually running the seminar) rather than a technical example. I find it much easier to understand something if the example is technical (e.g., an engineering project, building something, software, creating a new flying car), even if the domain of the example is not my domain.