Eric, I first made a shallow cut with an Exacto knife, then used a burnisher I made by using a standard size harness needle stuck in a piece of dowel. I ground off some of the point, then rounded the tip and polished it. I lightly wet the leather with rubbing alcohol, let half dry, then chased the knife cut with the burnisher. In the past I used a free hand type of stitching groover, but it never worked as well as I thought it should for doing that.
