Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, my top tip is to focus on maximizing each character’s strengths. Make sure to use key spheres to unlock important abilities early on, like getting Lulu to learn Doublecast as soon as possible.

For side quests, don’t miss out on the Celestial Weapons and Aeons quests. They can be challenging but totally worth it for the powerful rewards. And don’t forget about the Monster Arena – it’s a great way to level up and earn some cool prizes.

As for character builds, I recommend customizing each character based on their unique strengths. For example, Tidus is great for speed and agility, so focus on increasing his accuracy and evasion. Auron, on the other hand, is a powerhouse so prioritize his strength and defense stats.

Happy exploring!