how much (squaring) does it need? is it wonky? start with measuring, each side, top & bottom- then measure diagonally- top right to bottom left, top left to bottom right- figure out where it is out of square- then i generally try to find a straight line/seam that i can use to start- line up ruler- trim the least amount necessary to get that side straight- turn the quilt- line up bottom of ruler along the straight edge you just cut- (with any luck also lining up with a straight seam/line on the new side- trim- -- turn, repeat for all 4 sides.