This is a 'silly' rule that I have been using forever with my students, teaching them not to pronounce the last silent letters S, P, D, and T in French. It does improve their pronunciation when they realise this, and this silly rule helps them remember. I have done some exercises to go with the poster (The listening exercises don't have audio, so you'll have to use your own voice!). This is part of a longer module I have written mixing pronunciation and grammar exercises. I might share it with you soon!
Feedback much appreciated!