This may not apply to everyone but I think using the wii remote and nunchuck instead of a classic controller is so much easier. All you gotta do is keep pressing A. Also, if you turn the remote or hold it straight up, it will do different attacks. Also, I think it's much easier to swim using the wii remote.
When you are facing a tough monster on a quest (aka a barroth Dx, you can go back to your camp and heal on your bed. Thus saving on potions, or if you don't have anymore. This also heals poison and whatever. However, it doesnt heal your stamina so if you do this make sure you have lots of stamina healing items.
heres a good hint for Hammer lovers. If you need to sever a tail hammer away at it until the monster falls over 2-3 times then using throwing knives(grab from felynes)hit the tail(need 4-5 knives) if you did it right you got yourself a tail
If you have your weapon sheathed and a monster is attacking and your weapon has guard capabilities(Great Sword, Sword and Shield, Lance) by Squeezing R, X and A(classic controller) you can perfom an immediate block.
Jaggi/Jaggia are afraid of fire, by holding your lantern you can cause them to stay at a safe distance (some may attack before backing away again) but by hitting them two or three times with the lantern you can scare them enough so they run from the current area.