Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing on each character’s strengths. For example, Tidus is great for agility and speed, while Lulu excels in magic. Make sure to plan ahead and use key spheres wisely to unlock powerful abilities.

As for side quests, don’t miss out on the Celestial Weapons, especially the legendary weapons like Tidus’ Caladbolg and Auron’s Masamune. They require some dedication to obtain, but the rewards are totally worth it. Also, don’t forget about the Monster Arena challenges for some tough but rewarding battles.

When it comes to character builds, experiment with mixing and matching different paths on the sphere grid to create versatile characters. For example, you can turn Lulu into a black mage who can also handle some physical attacks. And don’t underestimate the power of support abilities like Auto-Life and Protect.

Happy exploring, and may Yevon guide your journey through Spira