Now that's a hott tip! ;-)

-Will

Ha! The Invert command also works for selecting a vertices of a curve when doing fillet on a corners.

(Not really a secret, but a 'Maybe you didn't realize' ;-)...

Run 2 applications of MOI at the same time if you want to work in 2 seperate drawings at once. Ctrl-C, Ctrl-V from one to the other.

Hold down the Alt key while drawing to temporarily disable snaps.

Selection undo: If you make a selection mistake (like click on the wrong object or click in empty space accidentally and lose your selection you have built up), hit undo to restore selection back to its previous state. There is just one of these "selection undos" available so that the undo stack does not get filled up with a ton of selection stuff.