My favorite socks were starting to wear thin in the heels so I want to show you how I darned them. It really isn't hard. I have a wooden darning egg, but you could use anything hard and round, like a ball. I use embroidery floss and a hand needle.
Slide the egg inside the sock. I do not tie a knot rather I just weave the end in. Start stitching or weaving back and forth, horizontally, covering the area.
Then work the whole area vertically and then diagonally for really good coverage.
It blends in pretty well. Weave the end in and you are done!
The skinny handle on the egg is for gloves. I've repaired my favorite gloves several times.