Vinyl shoes are attractive, versatile and very popular this year. However, the rigid material doesn't breathe well and is difficult to stretch if the wrong size is purchased or the shoe is strangely uncomfortable. Here's what to do if the shoes are too tight:
Purchase a shoe stretcher. These are generally included with shoe stretching spray (which won't help you, as most are made for leather shoes).
With your home heater or hair dryer, safely heat the vinyl before you stretch the shoe. The heated vinyl will be far more malleable.
Use the shoe stretcher while the shoe is still hot.
If the shoe stretcher is difficult to handle or you simply can't find one, switch the shoes and wear them around the house. Put heavy wool or cotton socks on before you do this. The increased size will help stretch the shoes and will protect your skin from the heated vinyl.
Have patience. Walk around the house and be sure to reheat the shoes every 15 minutes or so. Spend a couple days on your project. Vinyl shoes are not easy to stretch and will retake their original shape if not properly and thoroughly stretched.
Don't attempt to wear your shoes out too soon. You'll end up with sore feet. Don't get too overzealous about your task. You may stretch the shoes too far. Don't heat the vinyl too much. You don't want to melt the shoe or burn your wool socks.