Whether you've lost weight, found the perfect pair of shorts that are just slightly too big or want to alter children's summer clothing, taking in a high-waisted pair of shorts will allow them to fit properly around your waist rather than falling down to your hips. Making the waist smaller with darts gives a neat, almost invisible finish; either sew them by hand or with a sewing machine.
Turn shorts inside out, and iron flat. Put them on, keeping them inside out.
Make two small darts on both the front and back of the waistband by pinching the fabric together, making four total. Pin the darts in place so the shorts will fit around the waist. Make each dart halfway between the center of the waistband and the side seam (these don't need to be measured exactly at this stage). If you are fitting the shorts on yourself, ask someone to help you with the back darts.
Carefully remove the shorts. Make the darts evenly spaced by measuring the distance between each dart and the nearest side seam, and measure each dart to check that you are taking out the same amount of fabric at each point. (The front set of darts do not have to be the same distance from the side seams as the back ones; make the front darts symmetrical to each other and do the same with the back dart.) Take out the same amount of fabric from the front of the waistband and the back, otherwise the side seams will not lie straight down your legs.
Try the shorts on again to check that you are happy with the fit. Experiment by moving the darts closer or farther away from the side seams to see which gives the best fit. Once you are satisfied with the placing of the darts, taper these gently, pinning them down into the shorts to make a triangular shape about 1 to 2 inches. This prevents the fabric from bunching round the places where it has been taken in.
Remove the shorts. Tack the darts by hand with the white thread, removing the pins as you sew. Tacking stitches (also known as basting stitches) should be big and visible, and don't need to be too firm; this stitch will replace the pins before sewing the darts properly.
Sew the darts in backstitch with the thread that matches the color of the shorts. Do this either by hand, or with a sewing machine. Finish off the loose ends of thread by hand by sewing several stitches on top of each other.
Remove the white tacking stitches with the stitch ripper. Iron the darts flat, making each one point towards the nearest side seam rather than towards the center. Sew the top of the darts to the waistband in the matching thread with a hemming stitch (catch the dart and the waistband together with each stitch), and finish off all loose ends.
If your shorts are white or pale-colored, use tacking thread in a contrasting color so it is easy to remove later.
When pinning a waistband, point the sharp ends of the pins towards the floor to make it less likely that you will get pricked.