When an email requires a follow-up, use the drag-and-drop method:

Simply click and drag the email, and drop it onto the bottom left “Contacts” symbol on the navigation bar.  Suddenly you’ve got a brand new contact with the email address and name automatically entered. Now, inside the Contact window, the Notes portion will have the person’s phone number and address (if included on their signature line).

• Use Copy (Ctrl C) and Paste (Ctrl V) to get the signature line items into the correct fields in the new contact window. Less typing, no typos--and your contact is created within seconds!
•  “Drag and Drop” the email again onto your “Calendar,” and an appointment will be made. Plus, it keeps all the detail from the email. So you won’t have to re-type into the appointment.
• “Drag and Drop” an email onto the Tasks or Notes symbols on the Navigation bar.

You can also reverse this:

• Drag any contact to Mail on the folder pane to create a new email to that contact.
• Drag any contact to Calendar to create a new appointment.
• Drag any contact to Tasks.