Talk to Cid and Auron a few times then go around the cabin. Talk to Rin and get some items for the upcoming battle. Make sure you put on armor that makes your defense go up about 10%. And get armor with SOS Regen and SOS Overdrive abilities.
Evrae
HP - 32,000
AP - 5,400
Weakness - None
Steal - Water Gem
Keep in mind, Evrae cuts all Fire, Water, Thunder, and Blizzard spells in half. So if Flare or Ultima are available, use them on Evrae. Its more useful to cast slow on Evrae and Hastega on you all. Evrae is basically immune to all the breaks and other attacks. So those are quite useless. When Evrae breathes in, have Cid move the Airship back. Make sure you have lots of Al Bhed Potions and Mega Phoenixes to keep your party alive. Really! You need it. Near the end of the battle will cast Haste on itself. So when he moves in, watch the CTB window for Cid's next turn. Make sure Rikku or Tidus are in the party, then move back after nailing Evrae. He'll move foward right away, just keep using this tactic and you'll win for sure.
