Preparation for SCEA

[ahmad namini]

I have been working in the Java realm for a few years and also have extensive in C++ and was once a member of that "other religion."
Currently doing lots of work with JBoss, Struts, Web Services (RPC- and Message-style)
and XML. I have a great love for computer science and in particular distributed computing.
I am a SCJP and shortly should become be a SCJD. By the end of the summer I envisage taking my SCWCD exam, at which time I will begin my quest for the ultimate prize, the SCEA.
My question is that I hope to be prepared for the late fall, what advice on long-term preparation would you suggest? Even if some topics are not required of the exam, I still hope to learn to be the best EA I can be.
Certain weaknesses I feel I have is clustering, performance tuning, and unit testing. Any suggestions?