Basics: How to Make Pointy Corners

I know of two ways to make pointy corners on cushion covers.

For the first one (on the left), cut away the excess fabric between the seam stitches, being careful not to cut through the seams themselves. While this works 90% of the time, there is an element of lucky folding involved when the corner is turned right side out, and the cutting needs to be done carefully.

For the second one (on the right), sew one seam, in this case the vertical one. Then fold the fabric along that seam, and sew the horizontal seam. When the corner is turned right side out, the excess fabric lies flat. No cutting needed.

For cushion covers, I usually sew the two side seams first, then the top and bottom.