Clean the surface of the object to be affixed first, and then stick the non-slip sticker on the surface after it is completely dry. If the instep is relatively thin, and there is a gap between the shoes and the instep, you can try this: add a half-size insole to the shoe head, and then add a layer of insole on the top, the insole of the whole foot, it is estimated that this will not be large. The thickness of the insole can be selected according to the actual size of the spare, and a lot of large insole can be selected slightly thicker.