Outlook isn't all that complicated to use once you figure it, but trying to explain how to do something in Outlook often takes longer than just showing how to do it.
Many of these tutorials area also available on Slipstickcom's YouTube channel.

Outlook Categories and Color Categories
This page sums up a few things I've learned about Outlook categories and color categories, with suggestions for using and managing categories along with troubleshooting tips. Outlook has always supported categories; through Outlook 2003, they were simply Categories. Outlook 2007 introduced Color Categories by merging the short-lived colored flags with categories.

To Secure Your Personal Folders (*.pst) File
How to password-protect Microsoft Outlook data files so other people can't read your email or view your calendar or contacts.

How to Remove RSS Support from Outlook
Not everyone likes RSS support in Outlook, fortunately you can disable the RSS capability using group policy or a registry tweak. You can also remove the RSS folders from your profile. I'll show you how.
How to Uninstall Outlook from an Office Installation
How to uninstall Outlook without uninstalling other Office applications.

Outlook Categories, Flags, and IMAP Accounts
Categories and flags are not available in all of my folders in Microsoft Outlook. I can use categories and flags on mail in my POP3 account but categories are not available in my IMAP account and flags are limited to one flag, no reminder. Why? The IMAP protocol doesn't support the Category and Flag properties

Adjusting Outlook's Zoom Setting in Email
New to Outlook 365: Remember Zoom Preferences. If the fonts in incoming messages are tiny (or huge), you may have a Zoom problems. I'll show you how to fix it. If you don't have an Office 365 subscription, I have a macro that will set the zoom level for you.

How to move IMAP data files
How to move an Outlook pst file used by an IMAP account or the ost file used by Outlook 2013 IMAP and EAS accounts. . Instructions include steps to move the pst or use the ForcePSTPath registry key.

Online Services in Outlook: Gmail, Yahoo, iCloud, AOL, GoDaddy
How to configure email accounts in Outlook, including Gmail, Hotmail, Godaddy, and Yahoo email. We have a list utilities that work with some web-based email services.

View a Two Week Calendar
You can select 2 or 3 weeks in the navigation calendars and view those weeks in a monthly-style grid. This trick works on all versions of Outlook. To change the number of weeks in the calendar view: Start with any Day/Week/Month view Drag the mouse over the dates in the navigation calendar to select up
Add Holidays to Second Outlook Calendar
As many users have discovered, Outlook's Options > Calendar Options > Add Holidays only adds the holidays to the default Microsoft Outlook calendar. Many users wonder how they'll get the Holidays on the other calendar. It's easy - add the holidays to the default calendar then move or copy them to the other calendar. Outlook

Open Hyperlinks in an Outlook Email Message
Use an Outlook macro to open every hyperlink in the selected email message. A version of the macro will open hyperlinks in every message in the selected folder.

Daylight Saving Time Calendar Display Bugs
When you the week starts on the Sunday Daylight time starts, appointments may appear at the wrong time in the week view.