I've done this two ways, and both of them involve (EDIT: I linked the wrong bulb, and Basil's suggestion is a better choice!)
No matter which method you use, remove the plastic housing around the LED bulb. Makes the LED much brighter.
Then, you have two choices. Create a reflector out of aluminum foil to put behind the bulb, or paint with bright white paint instead of making a reflector. I've also seen this done with a soda can cut up, but the reflection is not as high. The bend of a soda can is a perfect fit behind the bulb, though.
Last edited by tekkguy; 02-21-2013 at 03:32 PM.
Reason: removed link