Hey fellow Final Fantasy X explorer! When progressing through the sphere grid, focus on unlocking key abilities and stats for each character. Try to balance between improving their strengths and shoring up their weaknesses. Don’t be afraid to backtrack to grab missed nodes or farm spheres for customization.

For side quests, definitely don’t miss out on the Celestial Weapons and Aeons. They can be a game-changer in tough battles. Also, completing the Monster Arena and capturing all monsters is a great way to power up your team.

As for character builds, tailor them to your playstyle. For example, Tidus can excel as a speedy physical attacker, while Yuna can focus on white magic and summoning. Experiment with different paths on the sphere grid to find what works best for you. Happy exploring!