i've done it two different ways.
the first time i lined up all the seams and intersections from both sides by sticking straight pins through and then basting into place. then i used quilting that worked well with the block designs on both sides.
the second time, i just made sure both sides were properly aligned at the borders, accurately squared off, and smooth to the batting from both sides. i also did my best to make sure the blocks on each side were laying properly within the layout of their respective tops. i spray basted both sides, as well. then i used an edge-to-edge motif so none of it had to line up or fall specifically anywhere on either side.
the first method is infinitely more tedious.
the second works well. i'd recommend not using complex blocks on both sides. complex on one side; very simple on the reverse. that way, if you decide on fancy-shmancy quilting that enhances the complex side, it will also look great on the back.
