Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing on each character’s strengths. Use key spheres to access powerful abilities early on. For side quests, don’t miss the Celestial Weapons and Aeons. Completing the Monster Arena is a great way to level up and earn rewards. For character builds, customize your sphere grid to fit your playstyle. Experiment with different paths to maximize each character’s potential. Happy exploring!