1. Make sure your high heels fit you by measuring your feet. Measure your feet in inches and buy shoes that fit comfortably and correctly. Measure your right foot , and then your left foot by standing with the back of your heels touching a vertical surface such as a wall with your feet on a hard surface. Press down on your longest toe and mark where it ends. Measure from the wall to the mark with a ruler to the closest and NEXT HIGHEST 1/16th inch. The following are US shoe sizes 7-10 followed by corresponding length of the foot in inches:
Size 7 is 9" + 5/16" Size 7.5 is 9" + 1/2" Size 8 is 9" + 11/16" Size 8.5 is 9" + 13/16" Size 9 is 10" + 0" Size 9.5 is 10" + 3/16" Size 10 is 10" + 5/16" Size 10.5 is 10" + 1/2" Search "women's US shoe sizes in inches" for a full list.
2. Try on heels starting with the size that corresponds to your foot size in inches. (Stay focused - no cheating by trying on too small really cute shoes!) Try on shoes that are up or down from your size, making sure that there is between 1/4" to 1/2" of space between the shoe wall and the tip of the big toe AND the tip of the longest toe when you are standing in the shoes. In narrow toe box shoes there should be room between the toes and the area where the shoe comes closest to the foot which is usually along the sides of the shoe. The toes should not be crushed from side to side by the tapered toe of the shoe. In sandals the foot should not be pressing into the straps of the shoe or be hanging over the sides or front of the shoe.
3. Walk about in the shoes that you have chosen. The shoes should fit so that you can easily wiggle your toes about when you are standing and no toes are pressing into the front of the shoe box. Your foot may start to slide forward when you walk if your foot is narrow, however when you are standing still there should be room at the toes end when your heel is firmly pressed into the heel end of the shoe. Your heel should not extend past the insole at the back in an open heeled shoe. The sole of the shoe should flex so the shoe does not come off at the heel end when you walk, The high heel of the shoe should be placed so that you feel balanced, neither tipping forward or backwards. Even perfectly fitted heels with inserts that keep your feet in the right place and provide adequate cushioning under the ball of the foot can be hard on your feet due to the ankle angle in heels, which is more and more pronounced the higher the heel or the shorter your foot length relative to heel height.
4. About 70% of women who wear high heels can benefit from inserts in them. You will likely be in this category unless you happen to have feet that fit exactly into standard shoe sizes in length, width and height on both feet. High heels can be improved in fit from inserts even for women whose feet don't have pain from heels to prevent toes overhang or heels gaping. All feet are susceptible to gravity which can move the foot away from where the shoe designer intended it to be and cause instability when walking. All styles of heels are easier to walk in with precisely fitted inserts that add stability by holding the feet firmly where they were designed to be. To be effective in holding back gravity the inserts should be able to hold back pressure without moving about, not become slippery when damp and not be so thick that they crowd the shoe or cause the foot to rise up out of the shoe and the shoe to fall off.
5. Never buy shoes that are too tight with the plan to stretch them bigger. Stretching shoes is usually doomed to fail, and in persisting you can damage your feet by subjecting them to shoes that do not fit properly or cause damage to the shoes making them unwearable. If you have bumps on your foot or toes that become sore when there is pressure on them your shoes should be roomy enough to accommodate your foot comfortably. You may need to buy shoes a half size bigger or styles that are open at the places where you have bumps. It may be possible, depending on the style and finish of the shoe, to cut short clean slits into the shoe directly over the area of the bump. These slits will open when you wear the shoe and provide pressure relief, but will close when the shoe is off.