Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, focus on unlocking key abilities for each character first before branching out. Make sure to use the teleport spheres to access other parts of the grid efficiently. For side quests, don’t miss out on the Celestial Weapons and Aeons quests for powerful gear. As for character builds, customize each character based on their strengths – like magic for Yuna, agility for Tidus, and defense for Auron. Experiment with different paths to create a well-rounded team! Happy exploring!