Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing on each character’s strengths. Start by unlocking key abilities like Haste and Curaga early on. For side quests, don’t miss out on the Celestial Weapons and capturing all monsters for the Monster Arena. As for character builds, experiment with different paths on the sphere grid to maximize each character’s potential. Remember to strategically use stat-boosting spheres to customize your party members to suit your playstyle. Happy exploring!