You will need
7-8 inch circle of fabric (you can use a small salad plate to trace the fabric out if you are unsure of the size) or Spoonflower has a great kit here by Anda preprinted. We used Kona cotton for ours at the Etsy/Spoonflower Craft Party.
3-4 inch circle of felt
Step 1: Cut Out Your Fabric
Cut out a small piece of felt (3-4 inches) for the bottom. You can use a tall glass as the template for this.
Step 2: Sew Around the Edges of the Pin Cushion
When you have finished, pull the thread making a small circle to prepare for stuffing it.