I have Basic Seminole Patchwork by Cheryl Greider Bradkin if you can get a copy of it or one of her other books, she explains how to cut your pieces to fit around corners with straight cut pieces & with angle cut pieces, but I'm sorry I wouldn't be able to describe it, and I haven't done it myself.
Here's an article that might help
http://www.unitednotions.com/fp_aviary.pdf