There is something romantic about learning from a craftsman through apprenticeship. Something like the difference between reading a cooking book and following grandma around the kitchen. I had the opportunity to follow 10-year shoe maker veteran Alex Reed (http://www.alexreedshoes.com) around the Pier 9 workshop, and learn to make my first pair of leather shoes.
We had a book at hand called "pattern Cutting, Step-by-step patterns for footwear" http://noblefootwear.com/books-for-sale/pattern-cu..., and I'm not going to repeat the techniques. What I'm sharing, are some moments of learning for a first timer.
A last is a mechanical form you build your shoes around. It represents your foot, and your foot is not a flat 'size 40'. It has curvy profile lines all around.
Getting the Last perfect took half of my apprenticeship. Think about the last time you went to buy shoes. Size not right? Toes too tight? Try another pair. When making shoes, 'trying another pair' means that you go back to the last, add more volume or shave some down, cut more fabric, build another shoe, leave it on last to form over 24 hours, then try it on again. As a beginner, each iteration took me days. I got the shoes to feel right when I came to the 9th.
How many shoes did you try, till you bought your last pair of shoes?
Shown in the images above are two ways to deal with tightness in toe area.
Option 1. Add more length to the shoe, so the toes are not pushed against the front as much.
Option 2. Raise up the toe line to allow more room.
If you're using a physical last, the modification could be done with layers of leather. Multiple pieces could be layered up, glued together, and sanded down around edge for a smooth transition.
In a digital file (shown as in Autodesk Crispin here), you can modify the profile and fabricate again. We 3D-print ours in PC-10, and it works really well. I also tried Ultem, but it turns out to be really hard to nail into. For full report on experiments with 3D printed lasts, visit Alex at https://www.instructables.com/id/Last-Comes-First/