Go from this to this
For this icon I am using GIMP, it is very easy and therefore probably translatable.
Take your image and crop it, then resize to 100x100. Next copy the image twice, set the first one on soft light and the last on screen- then merge the layers. It should look something like this:
Next I used the white balance tool (colour-auto-white balance) and then sharpened the image. I then used the blur tool to smooth the skin and the sharpen tool to make Finn's eyes look a bit brighter. Then I used the dodge/burn tool set on dodge all over the icon.
Next is the colouring.
(set to soft light 23%) =
(set to soft light 25%) =
(set to overlay 37%) =
Next gradient and light texture (gradient made by me, can't remember who made the light texture, if you know let me know so I can credit them)
(set to overlay 100%) =
(set to screen 84%) =
And that's it!!
Hope it was easy to understand, if anything is unclear just ask and I will try my best to help :)
Also I would really like to see anything you make!!