First, turn the pants inside-out and try them on. Use tailor’s chalk and pins to mark how much fabric you want to take in. Sew on top of the original seam then gradually turn the stitch towards your marks. Then, try on the jeans, cut the seam allowance, and zigzag the edges, so they don’t fray. If the jeans gape at the waistband, pinch the fabric, pin it into place, and stitch two darts on top of your back pockets.