In the beginning, the larger size gave me more margin for error, but now I just find I prefer the size of the finished ear. For the foam, I’m using foam core board cut out with an Xacto knife. You want the outer edge to be smooth if you want your finished ears smooth. I like for the fabric piece to be much bigger than the pattern calls for, so that I have more fabric to wrap around the ear without burning my fingers on hot glue. This is where your fabric selection comes into play too. If you’re using a printed cotton fabric, it’s not going to stretch like an athletic leotard fabric. I have found that a fabric with a little stretch in it gives a much more polished look to the finished ear and will result in much less frustration to assemble. Some people like the look of a flat ear, but I prefer a fluffy ear. The size of your fabric cut will also depend on your fluffiness level. Some people fluff with cotton batting, or cotton balls. I’m using a polyester batting I found on clearance. (In general, you can find a lot of these pieces in clearance bins, since you don’t need a ton of fabric for each pair of ears.)
The ear is comprised of a foam backing, fluff, and finished fabric. Then you’ll adhere a back to a front, and finish off the outer edge with trim if desired. Line up all four foam pieces and make sure they are roughly the same size, and the edges are smooth, then set them aside. If using battling like I am, it can be cut to the same size as the foam and then set aside. Then lay out your fabric pattern and cut out 4 ear pieces. Be careful that the pattern is laid on the fabric the way you want the ear to look, which is more important with a directional pattern. When in doubt, remember it is always easier to trim excess than to try to add more! Of course, for this project I’m working with a black fabric, so a white fabric pencil, chalk, or metallic sharpie work well for outlining that stencil!