About the only things I can say are grab some paper, pencil and unloaded gun and start messing around with patterns, in general put your lines 3/4" outside the outline of the gun that will give you a pretty good idea of the size of the body (adds enough to mold around the thickness of the gun), then add your belt loop ears for a paddle style, or bend around the gun for a loop sewn to the back and an ear to the rear. There are some pretty good posts here with more details, most books and videos deal with revolver western styles. And there are pattern packs available. As far as molding goes it is basically wet leather that is pressed around the gun by using everything from your hands to smooth ball end tools and bone folders. Again there are lots of discussions about that too. Also there is a book by bianchi that is real good as far as history and tips, in the for sale section if someone hasn't already snatched up the great deal as it is hard to find at a good price, wish I had the money. Others will chime in because it seems that once you make a few you have a hard time passing up a opportunity to talk about them enough rambling on my part enjoy the adventure.