Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, focus on unlocking key abilities and stats for each character first before branching out to other sections. It’s important to plan ahead and tailor each character’s path to their strengths – for example, make sure Tidus learns Haste early on for agility in battles.

For side quests, don’t miss out on the celestial weapons and aeons. They require some dedication to obtain, but the rewards are definitely worth it. Also, keep an eye out for Al Bhed Primers scattered throughout the game as they unlock Al Bhed language, which can help you access hidden items and dialogue.

As for character builds, consider mixing up your party with different abilities to cover a wide range of situations. For example, Auron makes a great tank with high HP and strength, while Yuna can focus on white magic for healing support. Experiment with different combinations to find what works best for your playstyle. Happy exploring!