In mail view and tasks view, you can use filters to hide some items (items: Units of information in Outlook, such as e-mail messages, calendar events, contacts, tasks, and notes.), helping you focus on the items that are important to you. For example, to see only messages that are both unread and high priority, you could turn on both the Unread and High Priority filters.
Do any of the following:
Filter items in mail view
Filter items in tasks view
Filter items by category
Find items in Outlook by doing a basic search
Save a search by using a Smart Folder
Arrange and group items