Many Cosplays require high boots, often in various colors and shapes, which are hard to get.
So there are many techniques for making your own boots.
This tutorial shows only one possibility to make boot covers, but it allows you to make overknee boots from any short shoe.

If my Tutorial was helpfull for you, I'd love to see your results! You can also ask me any kind of question in the comment section or contact me on facebook:
www.facebook.com/CandFCosplayF…

Since this was quite fun to me... any suggestions for another tutorial? What are you interested in, to learn?^^

Have fun!