I'm taking a Go Pro to shoot some diving video, and I've never done this before. Assuming a mask mount is not an option, would you strap it to your wrist, attach it to your BC, or take it loose / on a lanyard with some sort of short pole? I've seen floatation mounts - are they recommended for diving?
Personally while scuba diving I have it on a monopod with a strap around my wrist. Not only does this prevent bubbles clouding your shot, it allows you to extend it beyond your normal reach.
Ever tried getting close to a shoal of fish? Near damm impossible. With an extended monopod, moved very slowly, you can get really nice shots.
GoPros have quite short battery life and it's not possible to change the battery under water. Therefore you'll need to turn it on and off. The best place to hold a GoPro is in the hand as you can frame the shot and hold it steady. Attaching it to a helmet / head strap results in lots of poor video which you'll probably throw away.
Either attach a bolt snap to the GoPro housing and keep it in your pocket on a bungee loop, or use a handle -- and add a bolt snap, etc.
If you're doing more photography than diving, a 'tray' style system is better with a couple of lights on handles either side.
Lighting is key to good underwater photography and GoPros aren't that good in really low light, e.g. UK diving, so you'll need additional lighting that is very wide-angle. The best lights are very expensive; many times the price of the GoPro camera.
I accidentally flooded my GoPro by failing to properly close the housing -- an expensive mistake. However, as an unintended consequence, my diving massively improved as I now enjoy the dive and not taking endless awful quality video!
I always use this.
It's a Hand grip, which is inexpensive and easy to use. you can attach it with the band to your wrist. That means you can just let it float if you don't use it at the moment. Then when you want to use it, just grap it again.
Also I would recommend to buy a red filter. The Light and the colors look much better and more natural.
Oh and btw. your remote for your camera wont work underwater. I made that experience by myself! :)
There are different ways depending on how you swim, take photo/film, etc.
A head mounted approach is easiest and shows people your POV (point of view), bubbles can be an issue depending on your reg and swimming position. But greater risk in losing it of your head. Some people hard mount it on a plastic type helmet (cycle/caving/construction) and then attach the helmet over their hood.
Some people like chest mounted straps as this is more secure, but you need to swim less streamlined else you only see the ground below you, which can be great depending on where you diving.
The other more versatile option is to place it on your wrist and then you swim with wrist pointing at what you want to film, also easy to remove and put on a stick if you want to get close-ups.
Each method will need some practice to aim correctly, but best is to try all three and find the method that gives you the best results.