Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing on unlocking key abilities first, like HP and MP boosts, before branching out to other areas. Don’t be afraid to backtrack to grab important nodes you may have missed.

For side quests, be sure to complete the Monster Arena challenges for some great rewards and tough battles. Also, don’t forget about the Celestial Weapons quests for ultimate weapons for your party members.

As for character builds, think about the roles you want each character to play in your party. For example, Tidus can be a fast attacker, Yuna a powerful healer, and Auron a tank. Customize their paths on the sphere grid to enhance their strengths in these areas.

Happy exploring! Let me know if you need more tips.