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.
Only one thickness is necessary for fitting. Turn shoulder seams toward front. Fold band on tracing and baste. Find center of band, place to center of neck, on right side of waist, pin edge of band on neck line of waist, being careful not to stretch neck; let end of collar band cover the one-inch extension. Waist Band: Baste a piece of tape or band made of cambric to waist at center back, ready to adjust fulness when fitting. Cuff: Turn edges of the single piece used for fitting, baste to place. Gather the bottom of the sleeves one-quarter inch from edge, leaving three-quarter inch plain each side of seam. Place cuff on gathers, letting the end extend one-half inch beyond placket opening on the upper side of the sleeve. Baste to sleeve.
Mark armhole, measure one inch back of shoulder seam on armhole. Fold armhole in half at this point, and at the opposite point, on the lower part of the armhole, mark the place for the seam of the sleeve. Then fold armhole again, so that the shoulder and underarm seams meet, and mark the points at opposite sides of armhole; between these points on the top of the armhole place the fulness of the sleeve. Hold waist on table with wrong side and lower part of armhole toward you; place sleeve so that the seam comes to the point marked for it; then pin sleeve in as far as it should be plain, but ease sleeve so that armhole will not be tight. By holding waist in this position, the sleeve will shape itself to the lower part of the armhole. Then gather sleeve between points indicated on armhole, using two rows of gathers, one on the traced line, the other one-quarter inch below it on the sleeve (this row is taken out when waist is finished). Adjust fulness, (holding armhole in same position), so that the greatest amount comes on top of the shoulder. Baste with small stitches.
See that all alterations have carried out what was intended. Look over sleeve. See that the straight grain of the material falls from the bone at the shoulder; if it draws forward or backward, rip and adjust the gathers. Notice the arm-hole line; correct line if not good. If the sleeve is too long, pin a tuck across it above or below the elbow, as need may be. If too full, rip part way at shoulder and pin tuck lengthwise to remove extra fulness. Notice the length and depth of the cuff, which are governed by individual taste.
See that the neck line as marked by the lower edge of the band is in good line, and that the band sets easily about the neck and is not too deep.
Make all corrections on paper pattern.
Irregularities in figure may be taken account of in the second fitting, making additional correction for the side which needs it.