Whenever you use the "New To Do" command the To Do editor displays an additional command:

"Save and Add" appears right between the "Save and Exit" and "Cancel" buttons in the To Do editor. When you click on the Save and Add button, the current To Do is saved and the editor box is cleared but kept open with the same settings for List, Priority, Sharing and all other controls. You can therefore enter several new To Dos into the same list, or same list and priority, in very quick order.
For instance, if you were creating a new To Do in your "Cars" list, and if you had assigned it a priority 2, when you click on Save and Add the new blank To Do will also have priority 2 in the Cars list.
Now if only there was a way to complete the To Dos as quickly as they can be created!