It looks, to me, that the problem may be your borders. Measure the CENTER of the quilt and then cut the border that size. Then fold the border and top in half, pin the center of the border to the top at the marked fold, then pin the ends, then evenly fit the fabric in between. The same technique would work for fitting long sashing strips to the quilt sections, in case that is part of the problem. I hope that helps.
That is great advice for me too. Thank you. Yolanda Wood River