Since the above guys seem to do two piece holsters I thought I'd throw in my two cents on one pieces. I usually figure out a rough shape by bending the leather over the gun then cut out the piece I want to work with. I then wet the leather and do a light wet mould, just the basic outlines I'm not trying to bone it. Once it is close to dry I use an overstitcher to plot out my lines then proceed. Its been working well for me but I'm new to all of this so your mileage may vary.