Alright, if you've been playing the demo, here's some tips.
-Great Jaggi: Just go at it, try your weapon out. Great Jaggi's as weak as large monsters get.
-Tetsucabra: Uh, something about avoiding rocks. You can hit him while he's bringing up a boulder to stun him, sometimes; I think it's a certain rock you can interrupt. Also it has a huge head, so if you're running anything that can KO (as of the tutorial, Hammer/Hunting Horn/Charge Blade premades can all KO reliably), have fun.
-Gore Magala: Important thing is, if you get hit by a fireball or walk into one of those mist rings, you get this building bar under your name. You have to beat the hell out of Gore before this fills. If you do this right, you get a buff. If you let it fill, you get super debuffed. Otherwise, directly underneath the thing is fairly safe. He has a few different type of fireballs. He can fire three in a row, which all angle towards the center (in order he fires a shot to your right that angles to your left, a shot to your left that angles to your right, and a shot straight down the middle), several close range blasts, and in his very obvious rage mode he can fire shots that go for a distance then explode sequentially horizontally.
If you enter mounting mode, which is that thing where you're on top of a monster after jump attacking it and stabbing it with your knife, do one of two things:
-if the little monster head is green, mash x
-if the little monster head is red, hold R until it's not.
Fill the bar right before the monster head reaches your progress and you get a free extended period of vulnerability! Perfect to unload with your spirit combo/charge3/golfswing/wyvernfire/ultra burst/jam session/whatever.
edit: also if anyone's worried about the game not running well on the normal 3ds, don't sweat it too much. Game runs nice and smooth like on my vanilla 1st gen black 3ds; definitely around ~45 fps-ish.