Here are some step-by-step instructions on how I turned a boxy vintage cashmere cardigan into a much more fitted and flattering sweater.
My grandmother gave me this gorgeous rose pink vintage cashmere sweater a couple years back and though I've worn it from time to time, it was really too big for me and felt really frumpy. I finally took action and could not be happier with the result. It's very quick and simple. I will no longer sadly put those oversized vintage sweaters back on the rack at Thrift Town.
First, turn the sweater inside out and try it on.
Next, pinch off the extra fabric at the side seams, up through the underarm. You'll want to gently grade the seam toward the wrist so that there are no sharp angles in your seam.
Baste these seams in place and try the sweater on again to insure a good fit. Look for any gaping at the bust, and raise your arms to make sure the sweater is comfortable.
Machine stitch over the basting and trim, leaving a wide allowance of at least 3/4 inch. Now, if your sweater is old and somewhat felted already (as mine is), you don't need any special finishing, though you can zigzag stitch the selvedge if you like. Otherwise, I recommend serging to prevent fraying.
Here is my new and improved fitted sweater:
With the scraps that are left over from trimming your seams, you can fashion a fabric rose and sew or pin it to the lapel.
Et voila! I may still change the buttons, as I find them a bit stark. But overall, this is much more wearable.