I don't know any vids or such that specifically address clean edges. I just use a super sharp knife and strop it every few cuts with jeweler's rouge to clean it. The thing that makes a knife drag and grab is the oils from the leather. Stropping it will take that off and hone the edge to keep it sharp. If I have a tight inside curve to cut, I usually can use a large 1" - 2" round punch before I start cutting with my knife. I have one narrow knife that is good for curves and another wider one that is great for straights. I use both on holsters. Some pards use a head knife because of the versatility of the narrow point and the long straight edge of the middle. If you can cut it where you want it with one pass, it will be a cleaner cut, too. The rest is a matter of practice.