Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, focus on unlocking key abilities like Quick Hit for Tidus and Holy for Yuna first. Don’t be afraid to backtrack to optimize your character builds.

For side quests, don’t miss out on the Celestial Weapons – they are powerful and worth the effort to obtain. Also, completing the Monster Arena challenges can yield great rewards and help in leveling up your characters.

In terms of character builds, customize your sphere grid to suit your playstyle. Experiment with different paths to maximize each character’s strengths. For example, boost Auron’s strength and defense for a tanky build, or focus on Lulu’s magic for devastating spells.

Keep exploring Spira and have fun on your journey!