How are you ? Eventhough I passed partI in May2002, I could only finish the assignment in Oct2003 because of work and family stuff. The ones I focussed are :
1. Keep the architecture simple but consistent.
2. Focus on the ilities and mention why your proposed architecture is best suited for this system
3. Thoroughly go through the Petstore and Adventure builder website docs(http://java.sun.com/blueprints/code/adventure/1.0/docs/architecture.html
4. Keep the class diagram clean with domain classes only. NO architectural components like EJB etc. Thoroughly verify that you haven't missed any class that misses some use case stuff. I used stereotypes heavily in the diagrams that made the picture clear.
Hope this helps.