Note: This tutorial was used in PSP9 but it can probably be translated to other versions and other programs. :P Enjoy.
1. Find an appropriate base to work with. I will be using THIS base of Mischa Barton.
2. Crop your base down to an appropriate size, in this case 100x100.
3. Duplicate your base twice. Change the first layer's blend settings to 'soft light' 100%, the second to 'screen' 50%.
4. Create a new layer. Fill it with darkkk navy blue. Set your layer to 'exclusion' 50%.
5. Create a new layer. Fill it with white. Set your layer to 'saturation' 25%.
6. Merge all of your layers (layers >> merge all).
7. Hold Shift+H to get to Hue/Saturation/Lightness. Use the following settings: Hue 0, Saturation 20, Lightness 0.
8. Next, go to Adjust >> Brightness and Contrast >> Curves. Enter the following settings: Input 50, Output 0. If you are unfamiliar with curves a great tutorial by herdestiny HERE.
9. Duplicate the image you have right now.
10. Go to Adjust >> Automatic Color Balance. Enter the following settings: Strength 100, Temperature 6300.
11. Set the layer's opacity to 65%.
12. Merge all layers (layers >> merge all).
13. Go to Adjust >> Automatic Contrast Enhancement. Enter the following settings: Bias - Darker, Strength - Normal, Appearance - Bolder.
14. Duplicate your image
15. Sharpen the duplicated layer. Not very pretty right now, huh? We'll fix that :)
16. Using an eraser brush erase everything on the layer besides the eyes and mouth. You may want to change the brush size as you progress towards the face.
17. Finally I went to Curves once again and entered the following settings: Input 30, Output 0.
And look now! You've got a nice icon ;P You can also add text, gradients, textures -- anything! Be creative. This is simply a guideline. This being my first tutorial I'd love some feedback :D Thanks!