Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, focus on unlocking key abilities and stat boosts for your characters. Don’t be afraid to mix and match different paths to customize your party members to suit your playstyle.

For side quests, make sure to complete the Monster Arena challenges for great rewards and the ultimate weapons. Don’t forget to participate in Blitzball tournaments for unique items and gear. And of course, the Celestial Weapons quests are a must for those powerful ultimate weapons.

In terms of character builds, consider specializing each character in a specific role like tank, healer, or damage dealer. Experiment with different abilities and see what works best for your party composition. And always remember to have fun exploring the world of Spira!