When following this tutorial you should tweak the settings to fit your image. Otherwise you'll get an icon that's too green, too bright, too orange etc... etc...
1. Open your base image. I got mine here. Crop and resize to 100x100.
2. Duplicate base. Set to Screen, 57%.
3. Duplicate base. Drag to top. Set to Soft Light, 57%.
4. Flatten all layers.
5. The icon looked too bright so, I duplicated the base and set it to Soft Light, 39%.
6. Flatten all layers again.
7. Sharpen. Use the Blur Tool  over any parts of the icon that look over sharpened.
8. Create a new layer. Fill with E0B9A2. Set to Color Burn, 47%.
9. Duplicate base. Drag to top. Set to Screen 58%.
10. Duplicate previous layer. Drag to top. Set to Screen 58%.
11. Duplicate base. Drag to top. Set to Linear Burn, 38%.
12. Create a new layer. Fill with 52DD32. Set to Color Burn, 79%.
13. Create a new layer. Fill with ECC01C. Set to Saturation, 100%.
14. Merge all layers.