I don't play it anymore but here's some of what I remember:
An important part of the game is mastering the Free camera system as well as dodging, the top players I've met seemed to have forgone defense for skills and attack bonuses because they've mastered the patterns. I chose to save my money(Hearing and seeing people complain about money led me to this) but my ability to dodge well allowed me to survive while those who badgered me about my armor died.
The free camera system is beneficial as it'll allow people to target troublesome spots (poisonous stingers, Vicious tails,etc...) or make the fight easier by allowing you to trip the monster.
There are weapons the monsters have an element disadvantage too, I've forgotten most of it but R/ludroth, Lagiacrus, Giginox, (Great)Jaggi are weak to the flames. As well as weak spots, the head always hurts, but some enemies tend to have weaker areas.
In Caves, it's smart to have a weapon that'll glow in the dark like the Vulcanis so your team mates have less of an excuse to how you got hit by their swords. On that note, certain weapons have a specific combo pattern that you'll want to avoid that includes launching nearby people in the sky, try not to do that as it's really annoying.
You'll want to have the farm in the village maxed out to constantly be able to make more honey, blue shrooms, godbugs, sleepy fish, Dragon toadstools, etc... . You'll have to devote some time to gathering a lot of raw meat which you'll cook then gather more raw meat because you have no more, as well as gathering blue kelbi (those deers, knock them unconscious then "loot" them) horns for a potent formula. You'll meet the trade lady(online) that'll trade for some things like Honey and other essentials but you'll first need to have the for mentioned things in order.
Get a Great Jaggi's mask as soon as possible from the events quest online as it'll help increase your chances to get better materials at the end. This'll help getting materials for forging your desired armors. Don't forget to upgrade useful armor with armor spheres.