A shoe's insoles are one of the factors that determine its comfort level. Some shoes already come with a good insole, but others might not have adequate padding. You can purchase insoles to put into your shoes to make them more comfortable. Whether for a pair of athletic sneakers or stiletto pumps, insoles can help redistribute the foot pressure and reduce shock of a walker's stride. Since many store-bought insoles come in standardised sizes, you may need to trim them to fit into the shoe.
Check whether the shoe already has an insole that can be removed, and how it will affect the installation of a new insole. A removable insole is normally easy to identify because it tends to be thick and not glued down. Because it might be difficult to wear two padded insoles in one shoe, many insole manufacturers such as "Super Feet" recommend removing the original insole before cutting and installing a new one. Some shoes, like stilettos, have a very thin insole that doesn't need to be removed. However, if there is not enough space to add the new insole, take out the original one.
Buy an insole close to your standard size. If your shoe size is a half size, round up to the next full size. For example, if the shoe size is a 7.5, choose a size 8 insole. Larger insoles can be trimmed to fit a slightly smaller size.
Stand on the insole and trace your foot with a piece of chalk. When examining the tracing, make note of the amount of space between the chalked outline and the insole's edge. The foot tracing should be slightly smaller than the insole, with no more than 1/4 inch of excess space all around foot.
Trim the insoles using a pair of scissors sharp enough to cut through dense cardboard. According to the U.S. Patent for "Multilayered Laminate Footwear Insole," insoles are made of multiple layers of materials not easily cut by a regular pair of scissors. A pair of sharp heavy-duty sheers will trim the insoles more accurately. Cut the excess material around the toes and instep areas, as clipping these areas is less likely to disfigure the shape of the insole, as explained by Super Feet's "User Guide." Once the insoles are trimmed, they should fit properly into your shoes.
You can also trace around the original insole to get an outline to cut along, although this method may make the new insole slightly bigger than necessary.