Hi Carroll,
Understanding the ITTOs (not simply rote memorization), as you mentioned, is very important for passing the exam. To be more specific, I'd say that understanding the major ITTOs for each process is most important. The goal is to be able to call out a particular process (or, lets say, have a friend quiz you on a process) and then list off the major inputs, tools and techniques, and outputs (not necessarily every ITTO). From reading Rita and listening to the PrepCast you should have an idea of which ITTOs are highlighted for each process (and, conversely, which ones are less important). For me, practicing aloud or with someone else reinforcing the understanding and quickens the learning process.