In Outlook, I keep a very simple folder structure where every email that I flag goes into the same folder ("Follow up"). Each email is flagged by one of the Outlook defaults (Today, Tomorrow, This week, Next week, No Date).

In Todoist, I'm using Today/Tomorrow/This Week/Next Week as projects.

Currently, all my flagged Outlook emails map to a default Todoist project (in my case "Inbox"). It would be awesome if the flag on the Outlook email sends the task into the respective Todoist Project.