That really depends on the style. If there are darts in the blouse, taking it up from the shoulder seams will put the darts in an odd place. If not, I think I would use a combination of both taking in a bit at the sides and a bit at the shoulder seams. If you take it all in the shoulder seams, it is going to pull your neckline up too, so that is a consideration as well.

Thanks, Donna. No darts.