When you are sharpening freehand, at least at first, find the angle YOU like. Keep your wrist locked. What you can do is mark the part you have sharp with a black magic marker. Vary the angle until you can remove all the black. That will be what you are looking for. After you have sharpened that way long enough, you can tell by the sound it makes and the feel as it slides across the sharpener if you have it right or not.