Wheres a good place to get alot of exp?

i am only at the moonflow and i need to level up tidus and wakka

You are only at the Moonflow?

Well... try the Moonflow. That's really only where you can train if that is where you are. Hope you run into Ochu.

Mihen highroad, seriously once you get used to it the xp gained is amazing. Try it, see what you think of it.

Yes, Mi'hen is easy and gives you lots of AP and gil.

the little stretch between Mushroom Rock and Djose is excellent too, but much harder, and if you don't have anyone "stoneproof" in your party it might get you a game over...

Yep thats true.