I've had several questions on how I make the photo corners on my cards. I know there are a few different ways to do it. Here's how I make mine (BTW each square of CS will give you 2 sets of photo corners):
Line up 2 of the points on your paper cutter - making sure that the points are exactly in the middle of the cutting line - and press down to make sure the adhesive holds.
Take one of the halves of CS and place back on the cutter - using the gridline to line it up straight - and make sure the wide point is exactly in the center of the cutting line. Press down on the adhesive to make sure it holds and cut again slowly and firmly.
Take the halves and line them up evenly - then cut off the wide-tipped end w/ scissors. I eyeball this part and make the cut depending on how wide I want the pieces of the photo corner to be.
Stamp, sponge or leave them and finish your card: