A GoPro is not the right tool to get consistently good still photos, but it does do video very well. If you want to take high quality video (rather than just record memories) and not spend too much extra money, then an LCD backpack, a red filter and a tray are required. Without video lights, you need good ambient light, this means staying shallow.
There is a lot of information out there regarding settings, my standard settings are 1080/50 fps. Something that is hardly ever mentioned is FOV. The default wide angle setting is great for large animals close-up, for everything else, I think the medium and narrow FOV is better as it makes your targets appear closer.
[video=vimeo;100580912]https://vimeo.com/100580912[/video]