Step 5: Toolin'!!
The basic concept of tooling and stamping is wetting the leather then making impression on it with a tool / stamp and a mallet.
We'll begin by "caseing" the leather. We don't want it soaked, just dampened. A wrung out sponge or paper towel works well.
I'm going to use a pear shader to give a "irregular dimpled" surface. Set your tool / stamp onto the surface of the leather, hold square with the work surface and strike firmly. Don't let your tool slip or bounce around, but don.t death grip it either. If you have it, goof around on a spare piece of leather first. There's a virtually infinite number of designs that can be tooled on leather. Feel free to go free form and experiment. For this project I didn't want to detract from the beauty of the watch and hardware, but I didn't want it plain either. Random dimples is a good, attractive spade taker upper. I just randomly hit it all over, then tooled on the edge of the leather.
Once you finish, position strap in a around-wrist shape so that it will take that shape naturally in the future.