Remember you can learn more about Bill Kerr and Weeks Ringle at their website:
I am thinking of making one like this! I have the book Transparency Quilts and I really like several of the quilts in the book, and the whole effect.
He free motion quilted the circles and didn't worry about perfection. I like that. It looks great!
One of their newest quilts.
Same effect as the circles only a rectangular shaped design.
The best way to get better at machine quilting is to practice, practice, practice!