The best way to dice an onion is after you peel the onion slice lines in the onion about a quarter inch apart but not all the way through the onion. Then turn the onion and do it again making a square pattern with the knife on the onion. Then turning the onion on it’s side slice the onion into slices (they should come out as small rectangle or square pieces). Once you have finished slicing up the onion then scoop all the onion together on your cutting board. Take your knife and in one hand have the hand and with the other hand place it on top of the knife (dull side). Then slowly chop the onion into smaller pieces. When you are satisfied with the size stop.