Add a texture
To complete the image, open a texture, like the stoney one used here. Press Ctrl+A to Select All, Ctrl+C to Copy, and close the picture. Back on the landscape, press Ctrl+V to Paste the texture in. It’ll appear at the top of the Layer stack (assuming the previous top Layer was active when you pasted it in). Now, in the Layers palette, click where it says Normal and change the blending mode to Soft Light. If the effect isn’t strong enough for your liking, you can choose Overlay instead. Alternatively, if the effect is too strong, click on the Opacity setting and lower it. Any colour that’s in the new texture Layer will interact with the rest of the picture, so if you want just the texture alone press Ctrl+Shift+U to desaturate it.