Where is a good place to train and work on your sphere grid and and after..

Good places to train:
Thunder plains
The desert
Or zandakind - stay near a save sphere if you have problems

I have found a less hassling, and easier way to gain a bunch of AP,
But there are some requirements to this trick.
(A) You must have the airship
(B) You have to have all of the Thunder Plain monsters.
(C) You must have the overdrive=AP ability on your weapons
(D) You have to have a lot of Phoenix Down's
(F) You must have the overdrive mode On "Stoic", or you wont get the
Exp.
(G) Auto-Phoenix helps a lot.
(H) Capture weapons for the creatures.
(I) Comrade Overdrive setting (optional)

How to do it:
Ok, Now that your ready to Experience the Higher levels,
But be warned, you must make cactuar run, or beat him to get the levels.
Go to Calm Lands and make sure you have your Overdrive=AP weapons on
And go over to the arena, and play against Cactuar King (in zone
Conquer).
And when the battle starts, immediately cast Hastega on your party.
Cactuar should make his first attack, and if not, have the character use
A move that will hit cactuar king, and that character is set for the
Battle, but if cactuar king attacked, use a pheonix down on whoever died
And then attack. One thing you have to watch out for though, is to
Watch your timing, If he has a turn right after yours, then you should
Fix anything you have to, but anything you do just DO-NOT-ATTACK!!, it
Makes this match really hard, because he will kill 2 characters. Make
Sure your limit setting is either on stoic, or comrade, so his 100,000
Damage translates into that much AP. Ok, presuming you hit him with all
The characters you want to gain levels, continue to do a phoenix down,
Guard, phoenix down, guard, and after you've had enough, or you died,
You should have at least 100,000AP after the battle. (You get AP even
If you run away, or if up to 2 characters died!) After the battle, buy
More phoenix down's, save, use levels, and then do it again. Do this
For awhile, and the other monsters become a breeze!

The omega ruins, you can also steal good stuff there

go to Omega ruins, you get around 20000 ap every battle, but the fiends there are strong.

I think the best place is to go to the Thunder Plains.

Some good places to go after you get the airship are:
(in order of preference)
Omega Ruins; monsters include Master Tonberry and Great Malboro
Inside Sin; monsters include Adamantoise and King Malboro
Zanarkand; monsters include Dark Flan
Or you can go to the monster arena after building a good collection of Conquest and Original Bosses.

I hope the IllusionTyrant has helped...

Omega Dungeon

Really, if you just got the airship, the best place to go to is Omega ruins. The battles are tough at first, but if you are smart and get the fully powered-up legendary weapons, then eventually you can do 99999 damage on whoever you attack, no matter what. However, this is not the best place for high-level people, inside sin is the best place to train. Training is a lot easier if you have items to customize your weapons, armor, and aeons, so make sure that you go to the fiend arena in the calm lands.

The Omega ruins are good for training but watch out for the great malboro.If they cast bad breath their is a 90% chance you will survive.

The best place to build up on your sphere grid is the omega ruins the monster give you alot of sphere levels but make sure you use an aeon to fight the whole battle or you will be knocked out game over


Hope this helps ps you will have to search for the omega ruins ok hope I helped

Just two places [Inside of Sin] and also Omega Dungeon. INPORTANT NOTICE ...if you enconter a Big Green Malboro.DONT FIGHT just run because he is hard there is a 50-50% chance that you could beat him.TRUST ME) REALLY JUST RUN.

The Omega Ruins.