Maybe I can help there, i try to do the same thing. My way makes a very small beach but maybe you could fiddle with it. Grab your land layer and add an outerglow, size 10, 100% opacity. Leave the default colour as it is. Then add a stroke, size 1 and use the same colour as in the outerglow. Can't remeber if the stroke was set to normal or screen.

Hope that helps.

-D-