Final Fantasy X Tips

Kill Dark Aeons Easily
Have Yuna with a weapon that has the First Strike ability. Next fight until you have Yuna's overdrive gauge full and then you have to gain 1 million gil. Now go fight with a Dark Aeon. Yuna will attack first. Have her use her overdrive and call Yojimbo (that will have his overdrive full). Pay him 999,999 gil and he will perform Zanmato.

I heard that there was a certain gil amount for Yojimbo to perform Zanmato. I do not recommend to use this tip against Dark Yojimbo because you have to fight against him several times.