Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing 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 and the Celestial Weapons quests for ultimate gear. As for character builds, tailor each one to fit your playstyle – whether you prefer Tidus as a speedy attacker or Lulu as a powerful mage. Experiment with different paths on the sphere grid to find what works best for you! Happy exploring!