While pressure is applied to tap on the "brow" of the dent on the outside would be the thing to do. If you had a autobody spoon.
You apply masking tape over it so it doesn't damage the paint and lay it against the brow and hit the back of the spoon with your hammer while pressure is being applied to pulling the metal down. That brow is what is holding a lot of the dent up, so tapping it lightly is going to release it. But to hit it without having pressure pulling down is going to distort it. So you want pressure pulling down on it while you do it.