Use filtering to see only what you need to see. Changing the filter of a view is as simple as switching to a different view from the View menu. Powerful advanced filtering is available too. Categories help you track items regardless of what they are or where they're stored. Categories work as keywords, letting you pull together items of different types.
Notes are the ultimate catchall.
Definitely the most underutilized facility in Outlook, the Note facility is a free-form database for bits and pieces of information that don't fit anywhere else. Automatic date recognition is sensible IntelliSense. Here's our list of what we consider to be Outlook's ten most annoying features. Outlook's three multiple email personalities are confusing. Outlook's labyrinthine user interface is distracting and confusing, especially to new users.