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 to other nodes. Don’t be afraid to backtrack to grab important stat boosts or powerful skills. For side quests, make sure to complete the Monster Arena challenges for valuable rewards and tackle the optional Aeons for added power. When building your characters, consider specializing them in specific roles like physical attacker, mage, or support to maximize their potential in battles. Happy exploring!