I took a class. I can't imagine figuring it out by yourself. Making a simple flat is the easiest, high heels are tougher of course because its harder to make the pattern for the uppers.
The height and shape of the shoe are completely determined by the "last" which is a plastic or wooden form of the inside of the shoe. The last has to come apart so it can be removed from the finished shoe as it is not flexible like your foot is. Ccommercial lasts have albuilt-in "breakover" hinge that allows them to "fold" for removal and then snap back into place. Obviously to facilitate quick reuse for production. I have made lasts from wood (a lot of sculpting, about 40 hours worth) and I cut them in the middle at an angle and screw them back together. You can sometimes find lasts in antique stores but obviously it has to be the shape you want and in your size. You use rubber cement, or maybe epoxy, as well as heat, in making shoes and you have to talc powder the last to avoid sticking and to keep sap from the wood from gluing your shoe to it. In shoe making, the last shall be first.
Then you will cut the soles and tack them to the bottom of the lasts. You will develop a pattern for your uppers by draping paper over the lasts. You then trace out the leather (cause its stretchy) for an inner lining and the outside. You roll the topline on the outer, folding in topline tape to keep it from stretching, basting it with rubber contact cement until you can sew it (with a special sewing maching) Forming ans stitching the heel is tricky because there is extra stress at the top of the stitching to account for. A leather flap or patch can bridge the gap or it can be done with the topline tape. The inner lining and outer are now fitted together like two funnels and sewn at the topline, leaving an overlap of the inner lining for holding its position on the last with more tacks while the shoe is stretched and formed over the last.
Now you wet the inner lining and stretch it over the sole where it bunches at the bottom, securing it with the tacks until it dries in place. You ttnen remove the tacks and contact cement it to the sole. Slice off and sand the folds for a smooth surface. Now you lift the outer away and form the toe box and heel counter out of a plastic impregnated cloth (purchased specially for the purpose) that is molded with heat and your fingers (ouch). Done right, these will give the high heel shoe more stability. When cooled you carefully sand/grind the edges so they will taper and not show through the outer.
Now carve out a slot as necessary and insert the metal arch support, gluing and tacking to provide the greatest strength as this is a place where the shoe wants to come apart. Its these supports that cause the airport detector to alarm. These are found at a Shoe Findings and Supply wholesaler, usually one in each big city and may take some talking to get them to sell to you. Perhaps your local cobler can help with supplies. It helps to know what you are looking for.
