I made the hat out of fleece, again, for added warmth.
Measure the person's head dimensions, from the top of the head, to the base of the neck, from the front of the cheeks, to the back of the head, and also measure the width of the back of the head. Then make a shape similar to this using those measurements. (If you are feeling a bit uncertain, I'd recommend making a pattern of this entire project on graph pattern drafting fabric.)
Make the opposite shape for the other side similar to this. Then sew the two pieces together at the top.
Make a piece for the back like this, but longer than I've pictured of course, so that the ends meet up. Pin, and sew the back piece on.
For the ears, fold over and cut out a shape as pictured below. Sew together along the edges, leaving a bit of an opening towards the tip of the ear if you desire to insert a straw for extra support. Then, pin into place on the hat, where it suits you.
Stitch ear onto hat along the same stitch lines that were made in stitching the ear together. You can see that I basically stitched an upside down L in attaching the ear.
Yoda costume complete.