Here's a summer thrift store skirt rescue. With disclaimers.
I liked this skirt for the minty blue color and lightweight fabric. But it was a size 3X.
I tried a new technique for taking in the sides. It turns out that taking in the sides of a skirt is remarkably difficult. I thought it was just me but a professional seamstress confirmed that it is indeed hard.
The seams of a skirt are curved, especially around the waist and hips, and if you curve wrongly, the whole thing looks bad. If you are me, you keep pinning and repinning to get a fit to the point that a $1 skirt can have $50 of labor invested if you paid yourself a buck an hour.
My new workaround is to use the manufacturer's seam as a guide. This works best for a somewhat flowy skirt and is easiest with an unlined skirt.
Try the skirt on and pinch at the waist where it would fit. Measure the excess. Divide by half. (See this article for more details.)
Turn the skirt inside out. Measure in by the number calculated above and mark with a pin. Continue down the seam line, measuring the same distance and marking. Do the same on the other side.
Try the skirt on to verify the fit is OK. Then mark the pin line with washable marker. Sew along your line. Trim the excess seam allowance. Done.
For being a quick job, it didn't turn out too bad.
Now for the disclaimer. I choose poorly with my skirt, first with size. When altering down so many sizes, your end product isn't going to look quite right. For one thing, the darts will be in a weird place. My second bad choice was elastic. The elastic waistband in the back of my skirt totally messed up my simplified system.
Trust me on this one: Elastic is evil.