As others have said, the old monster hunter games are best played as a turn based battle. Take the fights slow. Stay safe and watch exactly what the monster does. Only go in for an attack when you know it's safe. You might time out on a few monsters the first time, but every hunt you will get faster, as you figure out both the monster and your own moveset. The caveat though is you need to make sure you're paying attention! Just going by feel will get you wrecked and you won't learn anything doing it. Always be watching and analyzing. You can spend 10 hours throwing yourself at the monster and get 10% better, or you can spend 1 hour learning the monster and get 50% better.

Another thing to be aware of is that these games are capital S Slow. Fights are going to take forever, and that's only going to get worse when you get into the guild quests, which are intended to be played with 4 person parties. Singleplayer health scaling was not added until World. If you've been wailing on a monster and it's just not going down, don't get discouraged. As long as you're doing damage and not getting hit, you've got 50 whole minutes to kill the monster. You'll get it eventually, I promise. Just keep at it and at some point you'll break through, and the thrill of having conquered what once seemed so impossible will bring you a rush like no other! Good luck, and happy hunting.