Make a pattern of the size of patch you would like, I used a sweater, can't really see in the pic but it had black elbow patches.
Cut two out from your choice of fabric
Pin and sew, to make sure you have them in the right place, I kept putting on and taking off my sweater.
If you like those, trying making some knee patches leggings made by Highstreet ($80.00 a pair). Saw these online and fell in love!
once again, I just don't love the hand sewing!