A good quality pair of leather shears (Wiss, Gingher, some Fiskars) will make a nice cut if you have the hand power. The rotary cutter is best on straight cuts. A swivel knife is for leather tooling or carving, not cutting. One makes a shallow slice and usually bevels one edge to raise or lower the figure being carved. Basic leather working guidelines call for a clean perpendicular cut, then using an edger tool to slightly bevel the edges top and bottom, unless it will be joined.There are different sizes of edging tools for different weights of leather. After dyeing, if you do, a product called gum tragacanth can be used to slick and burnish the edges. Does a good job of sealing edges up. Water works ok also if you burnish with a bone or antler or hardwood burnishing tool. That's pretty basic but results in nice smooth edges. There are many ways to do the same thing. I've also used sanding devices on thick edges, sure forms, skiving knives, they all work but that's kind of the basics for those who might be struggling with this step. Hope it helps!