I realise that there's a number of Instructables for this sort of thing already but I figured we can learn from each other's ideas.

Step 1: Assemble the Materials

For this Instructable you will need the following materials:

Part from a GoPro pivot arm (I had a broken one from the handlebar mount lying around)
20mm PVC pipe (you can get 2-3m of this from B&Q for under £2 and it even comes in black!)
Tennis racket over grip (you can get a pack of 3 for around £2.50 at Sports Direct, or possibly even cheaper on eBay)
Paracord (<4mm diameter)
Sugru
Sticker

You will also ned the following tools:

Hacksaw
Scissors/knife
Lighter

Step 2: Cutting the Pipe

Before you just go and take a hacksaw to it, think about how long you want the pole to be. Consider how and where you'll want to use it and think about what's commercially available to as they'll have done their research.

The GoPole Evo is 26"/66cm long, the Reach (which is telescopic) ranges from 17"/43.2cm to a downright excessive 40"/101.6cm and GoPro's new 3-Way is 20"/50.8cm long.

I'm going to make mine the same length as the 3-Way because it's not a bad length and it will still fit inside my hand luggage backpack.

So, having decided on the length, cut the pipe and give the rough end a quick sand down. If you want to spray-paint the pipe any other colour, do that now.

Step 3: Attaching the Tether

Credit where it's due as the idea for the next part came from looper383's Instructable. Using this setup if the pole breaks the camera should remain attached to your wrist.

Tie one end through the section of the pivot arm that'll be hidden inside the pole and feed the other end of cord through the pipe. Pull all of the cord through so that the mount is sat in the other end of the pipe.

Now tie a loop in the other end for the wrist strap. Try to get the knot as close to the end of the pole as possible. Trim and melt the ends to prevent it fraying.

Step 4: Sugru Time

Pull the mount back out of the pole so you can apply the Sugru. Make sure you don't pull it too as you don't want to lose the wrist strap inside the pole. Once you've applied Sugru, push/pull the mount into the pole and tidy up the seal.

The other end of the pole is somewhat trickier to both do and to explain. Using the Sugru you want to seal the end of the pole around the cord. Once that's done, leave it to cure for 24 hours.

Step 5: Get Grippy

You might have noticed from the photos I performed this step earlier but it's probably best to leave it until this point.

Starting at the base of the pole wrap the over grip around working slowly up in the direction of the mount. Cut a taper in the grip and secure it with the tape that came with it (electrical tape will also do the job).