I've written a short essay (1,500 words) on the Commission's communication strategy over the last 5 years and where it should go next. You can read it here. I personally think that the parties in the EP need to take on the task of communicating themselves and their European visions more clearly - I think that a more adversarial form of politics would help communicate what different parties stand for, encourage participation and, as a result, people would become more familiar with how the EU works in a general sense (after all, the general public isn't really interested in the detail of how national legislatures work). Of course, interest and partcipation can only ever be encouraged to a certain extent as the EU's very technical, but there's still a lot of room for improvement.
So I think that the Commission is limited in what it can do, but if it becomes more political, and the Commissioners engage more in the mainstream mass media, then it will provoke some reaction and interest. Risks need to be taken by backing plans more publicly, though they may fail in Council or in the EP.
In the essay, I take a very general approach, since it's short, and since I think that the Commission can only act to encourage participation and interest, and that it remains dependent on other actors to a degree to achieve higher levels of interest.