Essentially you will be looking at the scratch pattern. You want it to be even and uniform across the edge. As you go to the next stones you want to see the scratch pattern getting finer and finer at each level and the bevel becoming more polished. First step through will be setting the bevel and there is no point going higher until it's right. Look from the top of the edge and make sure that the bevel meets all the way along the egde. Also check for chips etc by looking from the side. Good luck