I like my calendars to be color-coded. It looks nice, and when you have a busy week it just helps make sense of your calendar at a glance. You can use conditional formatting in Outlook to automatically assign colors to calendar items using conditions that you create. This really takes the work out of color-coding your calendar!
Did you know that you can overlay multiple calendars in Outlook, rather than displaying them side-by-side? If you frequently compare calendars (including group calendars) or use multiple calendars yourself, you need to try this!