How to Darn a Sock?

You can use the darning technique to repair small holes in Cotton Baby socks and other clothing. With a darning needle and yarn, you'll form a network of stitches across the gap.
Instructions

1. Find thread or yarn that matches the sock in color and texture; you can use embroidery floss (a type of thread) to repair a crew sock, while wool yarn is appropriate for a wool sock. Choose a darning needle as well.
2. Place a lightbulb in the sock and position the hole over the lightbulb. Your needle will glide smoothly over the bulb's surface, making your stitching go faster.
3. Thread the darning needle with the yarn or thread and leave the end unknotted. The darning process should create a tight weave that makes knots unnecessary.
4. Start your work on either side of the hole. Take several small vertical running stitches in the intact fabric of the sock, about 1/2 inch to the left or right of the hole. Turn the sock upside down and make another row of stitches next to the first.Increase the number of running stitches you make as you come closer to the hole. When you reach the point at which the hole begins, your stitching line should extend from 1/2 inch above the hole to 1/2 inch below it.
5. Continue making vertical running stitches. When your stitching reaches the hole, take your thread or yarn over the hole and into the fabric on the other side, forming what resembles a vertical bridge over the hole. Stitching should extend 1/2 inch beyond the hole at both the top and bottom edges.
6. Cut the thread end once you have covered the hole with vertical threads and extended the stitching 1/2 inch past it so that both sides of the hole look identical.
7. Thread your darning needle and begin your work 1/2 inch from either side of the hole at either the top or bottom. Take the threaded needle and weave it under and over the vertical threads that cover the hole (as well as the vertical threads that lie within 1/2 inch of the hole).
8. Turn the sock upside down once you reach the opposite end of the hole, and weave another yarn strand next to the first. Continue stitching back and forth until you've completely filled the hole. Trim excess thread.

Tips & Warnings
Use a darning needle for your repairs. The eye of this needle is large enough to accommodate a thicker yarn.
Sew a running stitch by bringing the needle up through the fabric, then down again, then up again.
Space stitches evenly. Lay both your running-stitch lines and crosswise threads as close together as possible to create a tight weave.
You can replace the lightbulb with another round, smooth object of similar dimensions, such as a hard plastic ball.