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1. Take your base, sharpen it as much as you need. I didn't sharpen it at all, because it looked fine the way it was.
2. Duplicate the base and set it to Soft Light.
3. Make a new layer and fill it with a dark blue (#0d1739). Set it to Subtract (Exclusion).
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4. New layer, fill with a light brown (#c7b299). Set it to Color, %55.
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5. Another new layer, with the same brown (#c7b299) at Multiply, %45.
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6. New layer, fill with a dark blue (#0d1739) and set to Screen.
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7. Yes, another new layer - fill it with a peachy color (#ffe0c1) and set to Soft Light, %64.
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8. New layer. Fill with a dark blue (#001f49) and set to Subtract (Exclusion) at %57.
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9. New layer, fill with a light blue (#85dfe4) and set to Burn (Color Burn).
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10. Duplicate the base, drag it to the top, and set it to Soft Light. Yay, you're done!