Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, my tip is to focus on unlocking key abilities first for each character before branching out. This will make your party more well-rounded in battles. Don’t forget to use level 1 key spheres to access adjacent nodes early on.

For side quests, make sure to complete the monster arena challenges for some great rewards and tough battles. Also, don’t miss out on the Celestial Weapons quests for each character – they are super powerful when fully upgraded.

As for character builds, think about each character’s strengths and roles in battle. For example, Tidus can excel as a fast attacker, while Lulu is best suited for magic damage. Customize your sphere grid paths to enhance their abilities and create a balanced team. Happy exploring!