If I am doing straight lines from one edge to the other edge, I start at the edge and go to the other edge. This way you do not need to bury your ends because you will be putting on a binding. Also, every other line of stitching should start on the opposite side than you did the last line. If I am stitiching around objects or doing an outline stitch, I will start in the center and work myself out to the borders. I think as long as you have the quilt basted good, you should not have to worry about it shifting.