Gumpaste tip: Use cut-up sponges to support your gumpaste creations. Not only do they support the shape really well, but they also allow air to circulate, cutting down on drying time. - another pinner wrote.
This is a template that I came-up with and it worked out great. You will have to re-size it according to the size shoe that you need to make. To make the sole, I used a real shoe that I got from Wal-Mart, cut the straps off and covered it in plastic.