If you want to do it in a way that actually requires talent (ie. not just automatic filters and whatnot), you could do this: Make a new layer for the clouds. Airbrush them in white. Use the smudge tool to blend them (adding fluff). Alternately, paint the entire layer black. Change the blending mode to "Screen". Use the Dodge tool set to "shadows" . Fluffify with the smudge tool. Dodge the highlights for added brightness in the front which will help add depth. Mountains. New layer. Draw the shape of the mountains with the paintbrush tool in black or dark gray. Lock the transparency on the layer. Now switch to white. Bring your brush opacity down to around 15 or 20%. Go over the dark shapes with a few different natural-ish brushes. Continue until you've drawn the mountains to your satisfaction. Unlock the transparency and adjust the blending as needed.