In this paper we present our findings on teaching Object Oriented Programming (OOP) with BlueJ in the context of a one-semester programming course. Specifically, we present the evolution of the course, results from its evaluation and proposals for a more effective teaching of OOP. Our proposals focus on the way that the features of BlueJ, the accompanying textbook and the well-known guidelines for teaching object orientation with Java presented by the team of BlueJ should be used, in order to avoid some underlying pitfalls.