I have been having trouble covering my square cakes in fondant lately. They start to tear at the corners almost as soon as I place the fondant on the cake. I've rolled it to about 1/8 inch thick. I've tried rolling it out on shortening and on powdered sugar. I've kneaded it for 8 minutes. I can't figure out what I am doing wrong - I've covered cakes in the past without this having happened, and I don't think I'm doing it differently now, so I find myself in quite a quandary. Any advice you can provide would be greatly appreciated. THANK YOU!!!

There is a video tutorial on this on youtube, check it out. I always do the corners first. Maybe it's your fondant. Just a thought.