After pleating, I sewed the skirt to the bodice, and zig-zagged the top edge. There is a mild dip in the back, so I clipped that curve.
Then I pressed the seam up, making sure that the pleats were lying nice and straight.
Next, I pressed over the seam allowance on the bodice, making sure that the stitching line was covered.
Then I pinned the whole thing down. I’m not going to sew down the bottom edge of the bodice until I’ve done the shoulder straps, top stitching, and boning casing; but when that’s all done, I’ll run a line of top stitching along the bottom edge, going all the way through each of the layers to hold the pleats in place and make the skirt attachment even stronger.