>

open your image and crop it to icon size.

sharpen your icon once, or if it is lq as much as you think it'll need.

open a brightness/contrast layer and match your settings.
brightness ; +26
contrast ; -2

next open a selective colouring layer and match your settings.
reds.
cyan ; 0
magenta ; o
yellow ; -5
black ; 0

open a curves layer and match your settings.
RGB.

point one ;
output ; 150
input ; 144

point two ;
output; 79
input; 78

point three ;
output; 50
input; 41

open a hue/saturation layer and up the saturation to ; + 8

open another brightness contrast layer and match your settings.
brightness; +15
contrast; -10

and your done.
other examples.

PSD.

>

works best with screencaps.

open your image and crop it to icon size.

duplicate your base and set it too screen.

[optional] if still to dark duplicate the screen layer.

then add a brightness/contrast layer and set your settings to.
brightness ; +18
contrast; -17.

then add a curves layer and match your settings.
rgb
output ; 113
input ; 114

red
output ; 64
input; 72

point two
output; 53
input; 50

you may have to swap the order you put in the red points. just see what works best.

finally add a levels layer and match your settings.
0,0.82,237

and your done. (:
other examples.

PSD