I'm starting with this: (cap by me)
Duplicate it and set the top layer to Screen. Sharpen the Screen layer (Filters > Sharpen > Sharpen). Merge Visible, and I have this:
Open a new Curves layer, and Adjust the RGB to lighten the icon, and I usually adjust the Red, Green and Blue channels as well. For this icon I used: RGB, Red, Green, Blue. I now have this:
Above the Curves layer, open a new layer for Hue/Saturation (Layers > New Adjustment Layer > Hue/Saturation). Leave Hue and Lightness alone, we're only going to use Satuation. I adjust the Master level as much or as little as I feel looks good. Usually I adjust the Green, Cyan, and Blue layers as well. For this icon I used Master: Saturation +13, Green: Saturation +50, Cyan: Saturation +22, Blue: Saturation +25. It doesn't make much of a difference yet, but now I have this:
Above the Curves layer, but below the Hue/Saturation layer, make a new Color Balance layer (Layers > New Adjustment Layer > Color Balance). Midtones: Cyan-Red +20, Magenta-Green -2, Yellow-Blue +1. Highlights: Cyan-Red -32, Magenta-Green 0, Yellow-Blue -8, and Shadows: Cyan-Red +45, Magenta-Green +25, Yellow-Blue -8. Set the Opacity to 32%. This green tint is from a tutorial by kryicons. I now have this:
On top of the Hue/Saturation layer, open a new layer. I decided to fill it with a yellow-beige, I chose #E2DEB2.
Set the yellow-beige layer to Soft Light, and set Opacity to 35%. I have this:
I'm finished with the coloring. See the Layers.
I hope that was helpful and clear enough to understand. :)