Step One: Cut out a circle.
Step Two: Sew big stitches around the rim of the circle.
Here the finished shirt I embellished for Eden..
Here is another great idea...
So many patterns and possibilities.
Remember to use Fray Check on the edges if the fabric frays, so when you wash it it wont unravel. Lay flat to dry to keep the form looking the best.
These are called "YoYo's" and you can look up all sorts of ways to be creative with them.