First icon tutorial
Go from
to
crop and resize your image to 100x100. Sharpen if needed.
duplicate the base twice set both to screen (will depend on the image how many time you will need to do this)
open a new raster layer fill it with #090b2d set it to exclusion 100%
open another new raster layer and fill it with #f8e9e8 set it to mulitply 100%
then go to Edit -> copy merged. Then go to Edit -> paste as a new layer and set it to overlay or hardlight 100% opacity (it comes out the same on both settings)
final product
my layer palette
a few more icons made the same way
I hope everyone can understand this, it's the first time I've done one of these. I'd love to see how it works out for everyone