Hey fellow Final Fantasy X enthusiast! When it comes to sphere grid progression, I recommend focusing on each character’s strengths. For example, Tidus excels in speed and agility, so prioritize those nodes for him. Don’t be afraid to mix and match different paths to create a well-rounded team.

As for side quests, be sure to complete the Monster Arena challenges for great rewards and tough battles. The Celestial Weapons quests are also worth undertaking for powerful gear. And don’t forget about the Al Bhed Primers and Jecht Spheres for additional lore and bonuses.

In terms of character builds, experiment with different abilities and spells to suit your playstyle. Auron makes a great tank with high HP and strength, while Yuna is a fantastic healer and summoner. Remember to customize your armor and weapons to further enhance your party’s capabilities. Happy exploring!