Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, focus on unlocking key abilities like Quick Hit for Tidus, Flare for Lulu, and Hastega for Yuna. Prioritize maxing out each character’s section before branching out to other paths for a well-rounded team.

For side quests, don’t miss out on the Celestial Weapons. They require some effort to obtain but are totally worth it for the endgame battles. Also, don’t forget to complete the monster arena challenges for some great rewards and tough battles.

As for character builds, consider customizing your own path on the sphere grid to suit your playstyle. Experiment with mixing different abilities to create unique combos. For example, giving Yuna black magic or making Auron a magic user can lead to some interesting strategies. Have fun exploring Spira!