I fucking suck so very terribly bad at this game. And really, I've sucked profoundly at every Monster Hunter I've ever played. I can never understand what monster's tells are and when fighting against quicker and more slippery enemies like Mizutsune it just means I eat pretty much every single attack they deliver. I've bought MH Tri and MH World before and sucked horribly at both, only really progressing throughout the easier hunts in the game by tanking hits, healing pretty much constantly and sometimes avoiding damage by sheer miracle.
I have absolutely no idea how to get better at this fucking franchise. Maybe it's just not for me.
Play online and learn from others! That's what I did, it's amazing how much you pick up just by seeing how others evade every single monster attack. Before I played online I didn't realise the evade dive was immune to everything and you could dive through elemental beam attacks. I didn't realise how to shrug off blights with nulberries, or mud/soap with cleanser. I didn't know the fastest ways through the map, and playing online will show you the optimum route to the target most of the time. I didn't realise that, when a monster you are already struggling with is raging, you might as well pop around the corner, heal up and sharpen your weapon. In MHR you can pretty much pop back to base and restock.
Learning the tells only comes with experience, even if you are failing each time, there's a ton to learn. Did you know you can absorb Mitzusune's red bubbles for an attack boost, green bubbles for health, then use a cleanser to shrug off the soap effect and keep the buffs? I didn't until an hour ago.
Practice dodges, emergency wirebug evasions (ZL+B), wirebug recovery after getting knocked back, and blocks on izuchi until you're taking them down with ease, it's a weak monster. Spend a quest on just learning the moves, not trying to kill it, that's what I do.