I've got to agree with Sasha on this. I haven't had any luck with using the duct-tape wrapping itself as the pattern (lots of other people swear by this method, though). I am told that if you remove the sock (and the elastic it contains) after you cut out your pattern then you get a nice pattern-piece that doesn't stretch out of shape.
I prefer to make a last. For my court slippers, which are made with craft-felt at the moment, I just stuff the sock and tape last with old socks. This holds the shape of the last very well and allows me to pin the felt directly to the last. It also allows me add a nice little point to the front of the last.
For fighting shoes (which will need to be durable leather) I am experimenting with filling the last with spray-foam (minimal expanding). This seems to be strong enough to stretch wet leather on (I can pin directly to the last) but I don't know if the last will be re-usable (the ultimate goal). Friends have suggested using silicone sealant (the best idea so far) or wood paste (sorry, forget the name of the stuff) to create a more durable last.
One trick I have found to work well (with court slippers which don't see lots of abuse) is to use a lightweight material (a light canvas in my case) for the sole and then glue a leather sole on the bottom and put in a little stitching around the edge.
Resources for shoes:
I. Marc Carlson's page. The best on the web.
http://www.personal.utulsa.edu/~marc-carlson/shoe/SHOEHOME.HTMCynthia Virtue, Poor Person's Poulaines.
http://www.virtue.to/articles/poulaines.htmlI forget, but it's one my list.
http://www.cs.latrobe.edu.au/~pears/SCA/SHOES/shoes.htmlCompany of St. Sebastian homepage
http://www.wiredpalette.com/sebastian/The Tower of London put out a book on medieval footwear (based on archaeological evidence, so it's very nice). It was out of print last I heard (though there were rumors it was going to be re-printed) and it is generally available through inter-library loan.
Last, the Bibliotheque Nationale Francaise has an online exhibit of art depicting the 14th century (some of it may actually be from the 15th century, I believe). Some excellent pictures of footwear (particularly in the hunting scenes) that illustrate the sheer variety of styles available.
Some words of advice on footwear:
1) Take lots of time on the pattern.
2) Work in cheap fabric first to get the hang of fitting the pieces together. Thick felt (cheap) is a good substitute for leather (expensive) during this learning process.
3) Leather is not fabric. No matter how much you practice with fabric you will eventually have to bite the bullet and start working with leather. Don't expect your first effort to be perfect.
4) If you make the pattern using the sock and tape method, make sure you are wearing your athletic insoles inside the sock.
5) Take lots of time when constructing your pattern. The pattern generally takes two to three times as long as the rest of the construction process (in my limited experience).
Good luck.