1.) Do this tutorial
. Keep in mind that your clouds will be shaped how this is shaped.
2.) Duplicate your layer after merging all layers. Unsharp mask with amount set to 5.00. Guassian blur 10. Filters > Map > Warp on the bottom layer while using the top layer in all the settings. Repeat twice.
3.) Duplicate layer. Delete the extra layer. Fill the bottom layer with a sky blue. Go to Layer > Colors > Brightness-Contrast, and set the contrast pretty far up. Filters > Colors > Color to Alpha (choose black). Layer > Colors > Level. Bring the left slider on the Output Levels pretty far over. Layer > Colors > Desaturate.
4.) Duplicate your layer. Alpha to selection on the top one. Fill with a blue lighter than your sky. Fill again. Set the mode to color. Lower the opacity to 55.
5.) Go to your clouds layer. Go to Layers > Colors > Levels. Bring the very right arrow of your Input Levels to the left some.