Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, focus on unlocking key abilities like Quick Hit for Tidus and Hastega for Yuna early on. Utilize the “Expert Sphere Grid” option for more flexibility in customizing your character builds.

For side quests, don’t miss out on the Celestial Weapons – they pack a serious punch! Also, be sure to complete the Monster Arena challenges for valuable rewards and tough battles. Lastly, don’t forget to hunt down all the Al Bhed Primers for a special surprise!

As for character builds, consider specializing each character in a specific role to maximize their potential. For example, turn Auron into a powerhouse physical attacker, Lulu into a black magic specialist, and Rikku into a versatile support character. Experiment with different abilities and see what works best for your playstyle. Happy exploring!