I usually take a stitch in the ditch the whole quilt from side to side and then the top to bottom with a walking foot. That gives the stability to the blocks you need to deal with the blocks individually. I just finished a baby quilt with hand embroidered blocks this way. Then I free motion stitched around each design close to it's edge and filled in the background with a small filler design. It raises the design of the image up to make it the prominent part of the quilt and makes it very stable for many washings. I then put a design into the middle of the sashing strips. Press to "block" everything to square, cut away the batting and backing, apply the binding, Done!