If your database has a lot of tables and fields, you may have a long list to choose from in step 2 of the report wizards, making it difficult to know which fields to select. To make things easier, run the Analyze Reports function in the Tools menu. This function goes through all reports and marks each table and field used as "favorite." This may take some time to run, depending on how many reports you have.
After you've run this function, step 2 in the report wizards displays a button with beside Table. If you turn this on, the table and field lists show only those tables and fields marked as "favorites." Turn it off again to display all tables and fields.