Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing on each character’s strengths. For example, Tidus is great for agility and speed, so prioritize those nodes for him. Don’t be afraid to mix and match different paths on the grid to create a well-rounded team.

When it comes to side quests, make sure to complete the Monster Arena challenges for some great rewards and tough battles. Also, don’t forget about the Celestial Weapons and Aeons quests for some powerful gear and summons.

As for character builds, experiment with different abilities and spells to see what works best for your playstyle. Mixing physical attacks with magic can be very effective, so don’t neglect either aspect of your characters’ skills.

Happy exploring! Let me know if you have any specific questions or need more tips!