Hmmm, some really good stuff here. I will definitely have to try the mitered corner tip. Meanwhile, I have found this video to be helpful - my miters are better but still need to be stitched. But what works for one person might not for the next, so here's my contribution:
http://youtu.be/DVuQ0eiRS8U
And I have to say I love Sharon Schamber's methods. They have been a tremendous help to me.