My personal guide to this: Get Qurupeco Bow and whatever armor set (at LR I used Chainmail, which elementally isn't a wise choice - I'd reccomend Jaggi).
In water: Use normal attacks if it's in your face, but avoid body contact to avoid getting a nasty shock. At a distance, combine manual aiming and Arc Shots.
If you see it circling, don't shoot - sheathe your Bow and get ready to dodge a charge. Once dodged, it should be at Arc Shot distance.
Outside water: Keep your distance, spam Arc Shots liberally if it's outside Spread range. Don't sit in front of it to avoid getting shocked/body-slammed/bitten/tail-whipped.
No idea if any of this matches either video - I'm typing this on my 2DS, meaning no Flash. Hopefully this helps.