Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, my advice is to focus on each character’s strengths. Make sure to unlock key abilities and stat boosts along the way. Don’t be afraid to mix and match different paths to create unique character builds.

For side quests, be sure to complete the Monster Arena challenges for valuable rewards and to capture monsters for the arena. Don’t forget about the optional Aeons and celestial weapons quests for powerful upgrades.

When it comes to character builds, consider specializing each character based on their roles in battle. For example, Tidus can be a fast physical attacker, Yuna can focus on white magic and summoning, and Lulu can become a powerful black mage. Experiment with different abilities and see what works best for your playstyle. Happy exploring!