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. Don’t be afraid to backtrack to grab important nodes like HP, MP, and stat boosts. For side quests, make sure to complete the Monster Arena challenges for valuable rewards and tackle the Celestial Weapons quests for ultimate gear. When it comes to character builds, consider specializing each character in a specific role like physical attacker, mage, or support to maximize their potential in battles. Happy exploring!