Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing on unlocking key abilities for each character first before branching out. Don’t be afraid to backtrack to fill in missed nodes for stat boosts.

For side quests, be sure to complete the Monster Arena challenges for amazing rewards and tough battles. Also, don’t miss out on the optional Aeons and celestial weapons for each character.

As for character builds, tailor each character to their strengths. For example, Tidus can excel in speed and agility, while Lulu is great for magical damage. Experiment with different paths on the sphere grid to find the best builds for your playstyle. Happy exploring!