I need some tips on how to defeat Ultima Weapon. I've fought him 14 times..

Have one person in your group (not Squall) able to use items, and the other (not Squall) use magic....Use aura magic with one one, then hero with the other, if Squall is junctioned with Leviathon, he can revive the other fallen comrades, or if both other party members die, use phoenix pinion and both will come back....do this over and over.

Get your party really strong so you can beat him.

First, junction Alexander to someone (Rinoa would be the best choice because of high magic stats). You have to equip the REVIVE command on the character. Leviathan's RECOVER command would also be extremely useful during this battle. You have to kind of guess when Ultima weapon is going to do Light Pilar so you can right away use REVIVE command or use a phoenix down because it will atack right after that too, probably finishing another character off. You should also have one of your characters with magic maxed out. Mine was Quistis. You should make sure this character has at least 50 meteors wich you could have drawn from Ruby Dragon during the previous fights when entering this place. To finish this guy fast, cast meltdown on him, and shower him with three meteor spells which will do around 7500 damage each. For quicker results, have Squall lvl.100 with maxed atack stats and Quistis and Rinoa both lvl.100 with maxed magic and spirit stats, making Rinoa's Angel Wing and Quistis's Shockwave Pulsar commands deadly. Squall should just atack normally, and use Curaga on other party members when needed. Don't forget to press R1 to double the damage. This should do around 6000 damage. I finished this guy off in less than 10 minutes and with everyone alive with full health. The prizes for defeating this enemy are 100 ultima stones and 100 ap (I think). Well, hope I helped!!

What I did was keep squall on low helf and give him protect then when it's time for squall to make a command keep cancelling it untill you have a limit break then give him all you have got

Card Mod Lagauna and Bahamut Use Hero on two members Meltdown then let Squall die revive him and use a hero on him unhealed and use limit break Megaelixers work good just in case Hero's last 1.3minutes i think time well DONT FORGET DRAW EDEN Last GF

1. refine gilgamesh card in holy wars
2. before going to ultima, make sure squall has low hp for limit break
3. equip one char revive(alexander), and the other recover(leviathan)
4. junction "item" in one char, and use holy wars at the beginning
5. draw eden
5. use squall's limit break, do this until ultima is defeated, this should be just 3-5 renzokuken

I was reading these as I came to my fight with ultima weapon and ill admit... I was scared. But to be honest.... I beat him in 2 moves.... Ultima only hit squall once for 1700hp. Here was how I did it....

Squall lvl 78... Quistis lvl 61... Zell lvl 68.
Squall had health at 9999... Zell had health at 8400.... Quistis at 343... (I kept her low to try degenerator which is what I was using on the monsters throughout the caves.)

I had zell cast aura on squall (squall equipt with final sword "lion heart" btw)... Then on my next move I used squalls limit break which caused about 3-5k per hit... Then he went into the "lion heart" finisher which caused 8-9999k per hit..... And that was it..... Oh wait.... I forgot to mention I had Quistis draw eden beforehand. But yea... It litterally took me 1minute.
If squall didnt use lion heart my plan was just to heal and repeat the process.... Good luck.

Please note: once you get down where ultima is just use your move-find ability and use the save point right next to the last door and save before you fight ultima.