This is one of my favorite techniques which is simple sponging and masking then adding silhouette images, so quick and easy!
For the moon die cut or punch three sizes of circle from a sticky note. Place the smallest and start sponging the panel using a cloud template (find a free pattern on my blog here). Remove the circle mask and replace with the middle sized mask and sponge some more then remove the mask and add the largest and continue sponging.
Tip: when replacing with a larger mask, hold the panel to a light source and it's easier to place it evenly over the smaller masked area.
Here's another card from a few years back when I first came up with the idea for this circle masking technique.
Embossing Folder - Stampin Up
Perfect Layers Mini and Perfect Cutting Mat from Perfect Paper Crafting was used with a craft knife to cut the 1/16" 3/8" and 1/8" borders.