I've described it this way to a few teammates who are starting out and struggle with the same. Stand up straight and let your bowling arm hang straight down at your side. Rotate your arm outwards so your palm faces forward, fingers below the thumb. Somewhere between hanging straight down and palm forward is where your hand should be at release, closer to palm facing forward. Assuming you have a fingertip drilled ball and your thumb leaves the ball before your fingers, you will get good roll and require minimal effort.
Maybe the coaches are cringing now...but it seems to be a simple straight forward way to visualize a strong position.
I've had much less success when speaking about keeping the hand inside, leading with the ring, etc., etc.
S^2