Before pleating, I hem the two edges of the skirt. (This becomes the center back later on)
After the hemming is done, I laid out the skirt, folded in half on my table. Then I clip every 1/2” to mark for my pleats.
Then lining up the center front and center backs, I begin pinning each side, using the 1/2” snips to line up box pleats of 1”. By starting at both the center front and center back, there is relatively little fiddling at the end to make the whole skirt fit, usually it’s only a matter of unpinning and re-pinning a couple of pleats.
Next up: Sew shoulder straps & skirt to bodice