Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, focus on maximizing each character’s strengths. Start by following their designated paths to unlock key abilities, then branch out to learn new skills from other paths. Don’t be afraid to backtrack to previous nodes for stat boosts.

For side quests, be sure to complete the monster arena challenges for valuable rewards and tough battles. The Celestial Weapons are a must-have for end-game content, so invest time in completing the associated side quests to unlock their full potential.

As for character builds, tailor each one to suit your playstyle. Tidus excels in speed and agility, making him a great physical attacker. Yuna is best suited for healing and support magic, while Lulu shines as a Black Mage with devastating magic attacks. Experiment with different abilities and mix and match to create powerful combinations.

Happy exploring! May Yevon guide your journey in Spira.