Cutting out the pattern is fairly obvious I think. For all the corners and sharp angles I prefer to use a small circular punch (1-2 mm diameter) rather than cutting those as it often happens that you cut to far into the leather at one side which might later be the starting point for the material to tear apart. I also use wood carving knifes with rounded blades for all the narrower curves as I find this easier and faster than a straight knife.
Here is the most convenient method I found for cutting out all those little bulbs that decorate the pattern:

First cut a pine cone shape with a rounded blade,



then round off with a narrower curved blade

I also like to break the edges of the cut leather. There is a special tool (apparently called Edge Beveller in English) for that, which you can get at leather workers's supply shops. Breaking the edges makes for more wearing comfort/ less chafing and a nicer finish. According to my leather working books it also help preventing the leather to split at those edges. This and pre-punching the corners (see above) are not required from the standpoint of a proper reconstruction of course.







Total for copying the pattern to the leather, cutting it out, breaking the edges and oiling it with netsfoot oil (for 1 shoe): 2h 10min

Preparation for sewing the back seam: first pitch (if that is the right word in English) the yarn with shoemaker's pitch, then pull a couple of times through a piece of cloth to give an even surface.

Black shoemaker's pitch is boiled from black pitch, wood tar, way, turpentine and water. Black pitch is coagulated / reduced-by-cooking wood tar, turpentine is fresh resin from pine or larch trees.  I bought it at a shoemaker's supply shop, but the package didn't say anything about the ingredients. From the way it feels and behaves I would guess it is a mix of at least bees wax and some kind of veg pitch/resin. It is definitely harder than bee's wax. Afraid that's all I can say at the moment ...

This will make the yarn more resistent against wear and moisture.

For sewing I use blunt, flexible steel needles, as all the hole are done with an awl. Thos flexible needles follow nicely through the canal opened by the awl, be it straight or curved. Here is a good way how to thread the yarn so that it does not slip out again while sewing: