1. Make Sure Service Pack 2 for Outlook 2007 is Installed

2. Archive Old Mail in Outlook and Keep the PST File Small

3. Move Messages Quickly in Outlook

4. Create and Use an Email Template in Outlook

5. Undelete a Message Quickly in Outlook

6. Filter One Sender's Mail to a Certain Folder Automatically

7. Find Related Messages with Outlook

8. Search Inside a Message in Outlook

9. Find All Mail from a Sender Quickly in Outlook

10. Set up a Distribution List in Outlook

full list via about.com

1. Send and receive mail in plain text
2. Turn off new-mail pop-up windows
3. See more of your inbox by disabling the Reading Pane
4. Roll your own Contacts view

via cnet

1: Don’t click on attachments

2: Empty the trash

3: Archive mail

4: Minimize add-ins

5: Avoid large attachments

6: Abandon stationery

7: Eliminate third-party spam software

8: Perform mailbox maintenance

9: Trim/forward multiple accounts

10: Simplify signatures

via techrepublic