Pick a moon phase.
With any moon phase, you’ll want to start with a circle to get the basic shape. If you want a full moon, you can stop here.
For a crescent moon, or any type of waxing or waning gibbous, the simplest way to get a perfect moon shape is to stack two circles on top of each other. “To make a crescent moon, I make two circles and move the top one around,” says illustrator Morgan Dees. “If you want a sliver you can make the overlapping circle really big, but if you want a thicker moon, make the overlapping circle smaller.”