I was just pointed at these tips on Office's site. Most are well known to experienced Outlook users, but I was surprised that I didn't know some of them:

• Flag that message fast  To quickly flag a message, select a message in the message list, and then press INSERT.
• Did you know that you can change the time periods shown in the Calendar grid?  In the Calendar time grid, you can change the default setting for 30-minute time slots to be 5-, 6-, 10-, 15-, or 60-minute time slots. Right-click the Calendar, click Other Settings, and then click the number you want from the Time Scale list.
• Move Desktop Alerts to a different monitor  If your desktop spans more than one monitor, you can make Desktop Alerts appear on any monitor you use. When an alert appears, pause your cursor over it, and then drag it to the part of your desktop displayed on the monitor you want to view the alert on.