This was made in Adobe Photoshop 8.0. and includes selective coloring.
>>
1. Duplicate your base and set it to SCREEN until it's bright enough for your liking.
2. Layer >> New Adjustment Layer >> Brightness/Contrast. Set the brightness to about 5 and the contrast to about 15.
3. Layer >> New Adjustment Layer >> Selective Colring:
REDS
Cyan: -30
Yellow: +30
Black: +10
YELLOWS
Cyan: +20
Magenta: +10
Yellow: +31
Black: -20
WHITES
Black: -20
NEUTRALS
Cyan: +5
Black: +5
4. One last selective coloring layer:
REDS
Cyan: -64
Yellow: +16
CYANS
Cyan: +100
Magenta: -19
Yellow: -65
BLUES
Cyan: +100
Magenta: -22
Yellow: -46
WHITES:
Yellow: -47
NEUTRALS
Cyan: +3
Magenta: +3
Yellow: -26
If you don't want this pinkish/magenta look, obviously turn this layer down or skip this step entirely.
5. For added color, go to Layer >> New Adjustment Layer >> Hue/Saturation and raise the saturation to around 15. Make sure you don't go overboard or else people will look orange.
6. Make a new layer and fill it with light gray (B7B7B7), and set it to COLOR BURN at around 40%, or to your desired level of darkness.
To sharpen I usually go all the way to the bottom of my layer pallete, duplicate my base, go to Filter >> Sharpen >> Sharpen, and set that to around 40%, or whatever looks sharp enough. I always sharpen at the end, because you keep duplicating sharpened layers, your icon will come out looking more and more jagged.
And you're done!
icons made with similar settings: