This section is from the book "Clothing For Women: Selection, Design, Construction", by Laura I. Baldt. Also available from Amazon: Clothing For Women: Selection, Design, Construction.
If the waist is good in line but appears generally loose, stitch inside the bastings on all seams; if tight, the reverse. If too loose, only at the waist, take in the seams enough to remove the fulness, sloping them off to nothing where the waist is correct. Usually this can be corrected in the seams of the side, back and under arm. If the waist draws in a deep wrinkle across the chest or back, just below the neck, take up the shoulder seam and clip the neck line enough to let the waist lie smooth. See Fig. 39A, shirtwaists. Where there are fine wrinkles which fall directly from the shoulder seams through the front of the waist, this seam should be opened and stretched upon the back seam enough to take out the wrinkles. Wrinkles which draw diagonally from the neck toward the armhole line may be removed if the shoulders are sloping, by taking up the shoulder seam at the armhole, slanting to do nothing at the neck (Fig. 39B). If such wrinkles occur with square shoulders, open the shoulder seam, keep the traced seam lines together, and slip the front shoulder down from the neck on the back shoulder until the waist lies smooth; then build up the front of the waist where it is short at the neck and trim it out at the armhole where it has been made too long. This latter alteration can only be made in a trial pattern, not in actual material, unless some device could be used for covering the join in the material (Fig. 39(7). Fulness at the armhole in front or back of a fitted lining may be removed by taking small darts in the lining (Fig. 79A). If the length of front and back measures have been taken too long, the waist may seem very full and drop in a couple of wrinkles across the back or front. In such case, pin a tuck in the lining where the fulness shows (Fig. 79A). If the waist pushes out at the hips because the length measures have been taken too short, slash the waist across shoulders or the bust and drop it down enough to set smoothly; then insert a piece of cloth in the opening (Fig. 79B).
Clip inside seam at elbow and two inches above and below. Draw the sleeve over arm, letting elbow rest in fulness at elbow point; draw upper part of sleeve to position, to see that it is of correct size, and long enough from elbow to top; also from elbow to waist, noting the width of the sleeve also.
Try collar to see if it is correct size.
Remove waist after fitting; trace alterations; open seams and trace new lines on other side of waist; make alterations on sleeve and collar. Rebaste waist; place sleeve and collar, for second fitting.
Fig. 79. - Alterations in close-fitted lining; A, dart at armhole to remove fulness. Also tuck across front to correct length of front; B, front of waist slashed with material set in, to lengthen front.