It's easy to add more folders to Outlook - right click on any folder and choose New Folder. You can change the folder type, if necessary, and change where the folder will be placed. You can put folders in the "root", along with the Inbox, Calendar, Contacts etc, or as a subfolder of any folder
Create a custom field for Outlook messages
How to create a custom field to mark messages that were responded to in Microsoft Outlook.
How to Export Outlook Data to a PST File
Occasionally you'll need to export data from Microsoft Outlook. Export is appropriate for moving calendar or contacts to another computer or backing up your calendar and contacts apart from your email, but should not be used to backup the entire pst. (Note Backup your contacts regularly if you sync with a mobile device.) To export
The No-Export way to use Outlook data in Excel
The no-export way to use Outlook data in other applications, such as Excel or Notepad.
Create a Contact Group from a List of Addresses
How to create an Outlook distribution list or contact group from any list of email addresses, including a spreadsheet in Excel or a custom view in Outlook (with only the display name and email address visible.)
Where is Outlook's PST file?
Beginning with Outlook 2010, Outlook uses the Outlook files folder under Documents as the default data file folder for .PST files used by POP3 accounts and pst files you create. When you do an 'in-place upgrade' any existing PST files will remain in their location, which is likely to be in the %localappdata% folder path.
Using Ctrl+F in New Messages
Some users are confused by the behavior of Ctrl+F in Outlook - sometimes it brings up the Find dialog, other times it Forwards the message. When the cursor is in the message body, Ctrl+F brings up the Find and Replace dialog. When the cursor is in the message header area, it opens a new copy
Disable Outlook's Conversation View
Outlook 2010 has a new Conversation view that groups messages together. Many users don't like it, fortunately its easy to disable, using one of two methods. Method 1: Right click on the row of field names and choose Conversations, Show Messages in Conversations. Method 2: Switch to the View ribbon and click on the Conversation
How to compact an Outlook data file (*.pst)
Outlook will compact the pst automatically when the amount of "white space" (space used by deleted items) exceeds 20% and it has some idle time. Outlook will work on compacting the pst when it and other programs aren't using all of your computer's resources and in most cases, it will recover the space within minutes,
Creating New Color Categories
How to create new color categories in Outlook 2007, 2010, and 2013.