Very simple tutorial.
First I start out with this icon of John Frusciante, which I sharpened before beggining.
Step 1: I duplicate the base and set it to Screen @ 50%
Step 2: Create a new layer and fill it with #a1fffe and set it to Burn (the color of this layer depends on the lighting of the image, you might have to fill it with #c1fffe, if it ends up too blue, or #85fdfb if it ends up too light)
Step 3: Create a new layer and fill it with #02033c and set it to Exclusion (again the color of this layer might be a darker blue, or a lighter blue, depending of the lighting of the picture)
Step 4: Duplicate the base and bring it to the top and set it to soft light
Other icons made using this tutorial: