I have better luck mitering corners with bias binding.

If you're talking about binding, check out Jenny Doan's onlline tutorial. You'll find it by googling quilt binding videos. I love her method -- it works for me every time! I've not done mitered borders -- I may do that at some future time, but not now. I can almost bet Jenny Doan has a tutorial on that, too!

For binding, the wider the binding the easier the miter, bias or straight. I like rounded corners myself. Gives the quilt something special and no miters needed.

Wow, Rhonda, that was a great video!