We are going to be going from this:

to this:

This tutorial works best with a picture of something with several primary colors on a white background.
1. First, add a selective color layer.
Yellows: -17, 0, +8, 0
Whites: -9, -5, +6, +13
Neutrals: -5, -2, +8, +6

2. Add another selective color layer.
Reds: -35, +2, 0, -6
Yellows: -42, +2, -26, -13
Greens: +100, -1, -2, +52
Cyans: +100, 0, 0, 0
Blues: +100, 0, 0, +19
Whites: +3, 0, -6, +3
Neutrals: -2, -1, -4, +9

3. Add
this texture from
dusty-memories and set it to color burn. Duplicate this layer if necessary to give it more depth.

4. Add a #080C34 color fill layer and set it to exclusion, 100% opacity.

5. Add a #8A2708 color fill layer and set it to lighten, 30% opacity. Add a white color fill layer and set it to overlay, 17% opacity.

6. Add
this texture from the same set at
dusty-memories and set it to linear burn, 50% opacity.

All done, yay! You may want to play around with the selective coloring layers a bit more, depending on your image. :)
Other icons using this basic coloring: