I've always found that the metal strap on my watch is slightly too big and twiddles around on my wrist. (The next adjustment down is slightly too tight.) Then I developed an allergic reaction to the back of the watch itself.
After seeing a few watches with leather straps that passed behind the watch back, I decided to design a fabric strap which would fit over the original and sit between the watch and my wrist. It works well. The watch no longer twists around; the strap is more washable than leather and more comfortable than plastic.
I've had several people ask me how I made it, so here you go. As a bonus, because this is a watchstrap, you get to see in real time how long it took me to make it!
This project will work best for a watch that is slightly loose on your wrist, and that has a strap with a catch or buckle which is not much wider than the strap. However, it's not impossible to accomodate a wider buckle.
Step 1: Materials / equipment
A piece of fabric, at least 10cm by 20cm (4" by 8")
Thread in a contrasting colour for tacking (optional)
A snap fastener (preferably plastic)
Paper and pen
Coin or round object about the same diameter as your watch face
Sewing machine (optional)
I have always used washable cotton fabric so far, but you could use anything so long as there is something comfortable next to your wrist. If you're buying material specially for this, 10cm off a roll will be plenty.