How to Take in a Jeans Waist by @Glitter+Wit
Step Four: Finish
Switch to your matching topstitching thread. You can leave all-purpose thread in the bobbin. Sew each line of topstitching from the bottom up, overlapping a few stitches with the old stitch line.
Clip any loose threads on the waistband and then topstitch–don’t forget to hammer out the thick parts. Reattach the belt loop (hammer, hammer, hammer).
Put your pants back on and Check. Yourself. Out.
You did it!