Monster hunter tri, need high rank help fast!

Hi, there.
May I ask what your fighting style is? It may help you get more helpful answers from the people here.

For Rathalos, I recommend you upgrade your Azi Dahaka to the Azi Dahaka+. Rathian+ armour would be ok if you get hit a lot, but Gigginox+ armour would work much better with the Dahaka as it gives Status Atk Up so you'll paralyse it more. Yet low def and fire res may be a problem. Later on in the game you'll want to learn never to be hit anyway, but it's up to you what armour you pick.

As for the battle, you'll want to stay by his legs if you can. Focus on what he is doing before you attack, so he doesn't fireball you when your in mid attack. If you keep a good offence, you'll end up paralysing him with the weapon I chose for you. Here, you can carry on attacking the legs and he might fall. You'll have to rely on your teammates for the heavy damage, as you're playing the support part with a status weapon. It's important you keep paralysing, as your damage output is low.

Remember than once a certain amount of damage is done, Rathalos will rage, so be certain you block his roar with your shield and stay away from his legs. After a roar always comes a fireball. It's crucial you aren't caught by his roar when you're underneath him or his fireball will be certain to hit you. Be careful – it really hurts.

For Barioth, I strongly recommend you upgrade your Qurupeco Chopper to the Djinn, or, even better – the Blazing Falchion. It needs Rathalos materials but with the mini guide above and good teammates, he'll just be a Qurupeco on steroids in terms of difficulty. Lagiacrus armour is nice for SnS, so I recommend that. Surprisingly, the Low Rank Lagiacrus armour is better than the high rank so make that. Just make sure you upgrade it in the armoury to have the same def as the high rank version.

For tactics, you'll want to try and break his claws first (the spikes on his wings indicate if they are broken or not). This will make him slip when he jumps, giving a large opportunity to attack.

The key here is not to be greedy. Barioth is fast. Very fast. Make sure you know if it's safe to attack, and be sure you have enough time to get away.

You can spend some time with the low rank Barioth to learn his movements, as this should help tremendously. Once you can kill him without taking much damage, move on to the high rank.

Once you can kill him, farm him for his SnS and upgrade it as far as you can go. It has a powerful ice element, which is Diablos' weakness. Use the Lagia armour again, and remember to bring ten sonic bombs. When he burrows, you can throw these and he'll act like he's stuck in a pitiful trap. Unleash a world of pain here while you have the chance. If he is in rage mode, do not throw sonic bombs when he burrows as they won't work.

When he isn't camping underground, attack his legs, but be careful. The same tactics for rathalos goes here – make sure you know you won't get hit as you attack him. If he tries to slam his hip into you and you can't get away fast enough, just block. I would not recommend blocking much in this fight though, as he drains a lot of your stamina and still does quite a bit of damage to your health despite the block. Rely on evading instead of blocking in this fight, but if you can't roll away in time, it's better to block than get seriously hurt or die.

I hope this has proved helpful. Took forever to write, but when helping others, I don't care how much time it takes.

If you're going to Sns, then don't bring a status weapon. For the Los, bring Lagia sns, I think that's your best bet. I think one of the best things about sns is your ability to ko a monster. Turn the wii mote on it's side and press A twice. Do that a few times on it's head and you should have him down. also If you can, bring traps. They help a bunch especially if you have flash bombs too. Pitfall trap him, fight, throw a flash bomb when he gets out so he falls and knock him out and then keep hitting... Then put another pitfall trap down and fight. Then flash and I think you won't be able to stun him again in the time it takes for him to get up. His main weak spot is his head so if you focus there, you should get him cap ready in under 10minutes ish. I'd probably use quru armor because of it's fire res and evasion+1. Also one trick about Los I've noticed is that when he roars, he kicks his leftfoot forward, so if you stand infrint of it, he'll kick you so you don't get hit by the roar. He also fireball-flies right after so if you can, try getting hit by his leg then through a flash bomb right away. Easy hits.
For diablos... Hmmm I'd say get the icicle spike but you can't deal with barioth yet...
So first get Los down and make the djinn sns. For Bari, I'd say use quru again because of evasion+1. I gtg for now I'll add more later.
Good luck
Edit:
One of the major reasons people don't like barioth is because it does a magical impossible jump the comes charging at you from the side. There's an easy way to dodge that and no one notices it. I'm not sure why but everyone gets rammed all the time. When u see him jump to the side and charge, just roll straight. If you were fighting him head on, the you'll be clearly away from his path. The pitfall-flash-stun-pitfall-flash technique will work with Bari too. And blos for that matter. Also try to break his wings asap because after you break them, he can't do the magic jumps and charge right after because he won't be able to make the landing right anymore.
After you're done with that cat, make the and because blow is extremely weak to ice. I really found blos easy with evasion+1. At this point you should be able to make Bari armor. Which is uber awesome against blow because you can evade pretty much everyone of his moves with it. Most people don't like his charge but with evasion+1/2 you'll easily be able to roll through it with the right timing. BRING SONIC BOMBS. Those will help a bunch especially since you can flash right after. I recommend not using your pitfall traps unless he is mad because you can't sonic while he is mad. Blos's main weakness is his chest so go for that.
That's all I got for you I think. Good luck.

Yeah. When you said that you were only good with sns, I assumed you had already tried the others, but if you haven't remember to try them soon because like MarioJr64 said, some monsters are easier with other weapons. Also if you have already tried other weapons but didn't like them try them again anyways, especially the lance. I remember my first time lancing I did pretty awful. I just noon charged everywhere. So I gave up. Then 100ranks later, I tried it again and it was pretty cool. You just have to get used to the moving and evading

Pfffft fine. I know for a fact I won't be a fan of great sword, I tried it a few times,(the kelbi killed me) if I had to pick secondary weapons now, probably lance and longsword, though rest assured, once I beat the game I'll become a warmonger who masters every weapon! Bowbun seems undesireable by the fact I'd be forced to make a new line of armor, that sounds like a job for aftergame. Bowgun seems good for teamplay, though I don't have teamplay. Once my brothers get back, I'll probably head to the arena where nothing matters and experiment on G jaggi or something.

Hi i would suggest for high hr rank do the online 2 star quest Wyvern Conversation 9000 dollars without sub b and a lot of hr... or peco... or rathian