If you have a GoPro camera, you’ll already be amazed at the quality of footage that can be produced by this tiny package. The two single greatest tips for shooting high quality video is to hold the camera steady and use lots of quality light. Many cave divers mouth their GoPro on their helmet, but this generally leads to frenetic video that induces seasickness in anyone that wants to watch your footage. Divers simply move their heads around too much as they look around the environment. 
To solve these two issues, Light & Motion has manufactured a compact tray system with articulating arms that carries two compact but powerful lights. The GoBe 700 Wide lights emit a strong but diffused beam that covers a wide area without creating hot spots. Check it out.
To further enhance lighting, consider adding a compact handheld video light into the mix. I use a Sola 2500 Video light in my left hand, freeing the right to operate my camera. If you give your diving partner a light or place one behind them, then you can further enhance your photo by separating the diver from the background. In the end, the more quality light, the better, so buy something that offers a rich, wide beam with a soft diffused throw that fills the wide lens view you get form your GoPro or other action camera.
