Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, make sure to focus on unlocking key abilities for each character first before branching out. Don’t be afraid to backtrack to grab important nodes. For side quests, be sure to complete the Monster Arena challenges for some great rewards. As for character builds, specialize each character based on their strengths – for example, turn Tidus into a speedy powerhouse or Lulu into a devastating black mage. Happy exploring!