This is how you can make a protective pouch for your camera where the strap on the camera will also be what keeps it inside the pouch. Sounds intriguing? Then stay with me and you shall become enlightened...

You will need:
A small piece of fabric
Cotton, needle, scissors
Card for a stencil

Step 1: The Stencil

Use your camera to measure how big the pouch will be. Just roll it over on the card as you mark off where the edges reach to. You will need about 1cm of space to sew the edges together. See the labels on the stencil shown.

Step 2: Sew the Open End

First, fold down the fabric of the end that will be the opening. Later on, you'll cut a slot out but for now just sew it as shown, leaving enough space for a slot to go between the thread and the edge.
Try to make a nice straight line with this thread as it's the only one you'll see when it's finished.

Step 3: Sewing the Edges

Then fold it in half, inside out and sew the two edges in the same way. If you have thread left over, you might want to sew over the edge as you see in the top left corner or even do this all the way around to make it less likely to come apart.

Step 4: The Slot

This part can be a bit tricky. I found my fabric to come apart quite easily so had to sew it a few times to hold it together. Because of this, I'd recommend using thick cotton rather than whatever this is (polyester?).
Anyway, first find the middle of the opening end, fold it and cut a little slot into it. You can do this on one or both sides. I chose to do one because of how weak the fabric was.
To sew it, it's done like around button holes on jeans and so on - lots of small loops close together. I had to do it in a figure 8 way (over then under) all the way around. This just needs to be big enough for your camera strap to fit through.

Step 5: Joining Forces

Then the clever bit comes in! I had no more drawstrings left so thought of using the camera strap as the pouch strap, too.
As you can see, you put the strap through the slot and then the strap through itself and, as if by magic, your camera can't fall out and you can prance down the road swinging your camera in complete safety! (Unless you hit a passing dog or a car)