Step 1:
Measure your shoulders from point to point to figure out how
much you need to take the pattern in, then add 1/2" for
ease and add seam allowance.
Step 2: If
you need to take the shoulders in 1" on each side, for example,
you would mark the shoulder point on the pattern 1" in and
blend the armhole from the existing bust line to the new mark
at the shoulder point.