The Outlook Windows program (not OWA) can be a productive tool once you tweak its UI, learn the keyboard shortcuts for your common tasks and learn how to find some useful tweaks.
Here are some keyboard shortcuts I find useful:
Ctrl + 1,
Ctrl + 2,
Ctrl + 3: Switch to Mail, Calendar, or Contacts view.
Ctrl + Shift + M: Create a new message.
Ctrl + Shift + A: Create a new calendar appointment.
Ctrl + R: Reply email to just the sender.
Ctrl + Shift + R: Reply email to all.
Alt + S: Send the composed email.
Backspace: Archive the current email or conversation.
Esc: Close currently open email window or any window or dialog.
Ctrl + Eor
F3: Switch to the Search bar at the top of Outlook.
Ctrl + Shift + F: Open the Advanced Find dialog.
F4to search in it.
Ctrl + Shift + B: Open address book to search for people.
Ctrl + Shift + G: Add a flag to current email.
Alt + Ins: Clear flag on current message.
Alt + Downor
Ctrl + .: Switch to next email.
Alt + Upor
Ctrl + ,: Switch to previous email.
Ctrl + Y: Go to a different folder.
Here are other useful features and tricks:
Customize existing styles or create new styles: I find creating my new styles useful so that I can apply them on parts of email. For example, creating a code style would be useful to apply on code snippets I paste or type into email.
To switch to offline mode: Go to the Send/Receive tab and click on Work Offline. This is great for working through emails without being disturbed by incoming emails.
To delay sending a email: Compose your email or reply in a separate window. Go to the Options tab and choose Delay Delivery in the More Options section. If this button is not present, click the ↘ and in the Properties dialog and set what you wish in the Do not deliver before option. The Delay Delivery button should appear in the More Options section after you use it once.
To import calendar file (
.ics): If you look for an import option in the Calendar, you will not find one! To import, go to File -> Open and Export -> Import/Export. Point to the file and import it into your Outlook Calendar.
To restrict conversation emails to a folder: Right-click on the conversation and choose Move -> Always Move Messages in this Conversation. This moves the conversation to the folder you choose and also all future replies to this conversation are moved to that folder automatically for you. Note that the rules you have set in Outlook will take precedence over this and so not all replies might end up following this order.