If you look around the forum there have been a lot of threads on this, because it is the most important part of honing. I had a quick look but could not find the pictures I am looking for. There are a few threads with great pictures through a loupe as to what a set bevel looks like. There is also a pretty good video on youtube by toxic? that explains spotting a poorly set bevel using a bright light. Due to the difference in peoples hair it is one of those test that also needs to be calibrate to your hair. It is a quick and easy test once you know what you are looking for. If you go to a meet you can see what others are showing you in a loupe and then test it on your arm hair. At home by yourself it is a lot of trial and error but getting a loupe and beginning to look at the tip of the apex is about the only way I was able to understand. Essentially looking down on the tip of the apex, it should have no sections of sparkle reflecting back. I will add links into this if I can find what I am looking for before someone else posts it.