Q You mention using "commonsense" knowledge to round out the class diagram for basketball. That's all well and good, but what happens when I have to analyze an area that's new to mewhere common sense won't necessarily help?
A Typically, you'll be thrust into an area that's new for you. Before you meet with a client or with an expert in the field, try to become a "subexpert." Prepare for the meeting by reading as much related documentation as possible. Ask your interviewee for some papers or manuals they might have written. When you've finished reading, you'll know some of the fundamentals and you'll be able to ask pointed questions.
Q At what point will I want to show an operation's signature?
A Probably after the analysis phase of a development effort, as you get into design. The signature is a piece of information that programmers will find helpful.