Grady Booch (the legendary methodologist) talks in an interview about architectural patterns. I loved one sentence from this interview, when he answered the question: "What are the hallmarks of successful large software projects?", he said:
"Here are the two rules, and everything else is detail. First, development should proceed by the successive refinement of an executable architecture. Second, the rhythm of a project is defined by a regular incremental and iterated release of those executables."