Pillow makers all over the world have different opinions on how to make the pillow corners. There are basically two ways to make them and they each produce a different look.
Many pillow covers you see in stores or ones you make using a sewing pattern are made with corners in a 90 degree right angle. When laid flat, the cover looks like a square. However, because pillows are 3-dimensional rounded shapes, covers made this way can result in a excess fabric at the corners, like a long floppy dog's ear. This problem increases in severity the larger your insert. Imagine putting a ball in a square bag. It would not fit as nicely as a bag that has some shaping to fit the ball's contours.
What I do in hand making all of Aloriam's pillow covers is to taper the corners so that the excess fabric are clipped off. When laid flat, the cover has gently curved sides that will straighten out when filled with an insert. This feature is often requested by interior designers because it corrects a pillow insert's tendency to be understuffed at the corners by making the corners more form-fitting. Even though the flat cover doesn't look square, the stuffed pillow will look square. Voila, no more dog ears!
This "trick of the trade" results in a professional, custom pillow fit that will make whatever insert you use look its very best. You won't find custom, labor-intensive features like this in mass-produced pillows.
You don't have to buy your pillow covers from me, but whoever you buy from, please make sure they are aware of this sewing technique so that you will have the best finished pillow possible.
Until next time, remember .... Life is too short for ugly pillows!