Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing on one path for each character to maximize their strengths. Don’t be afraid to backtrack to grab important nodes like HP and MP boosts. For side quests, don’t miss out on the Celestial Weapons and Aeons quests for powerful gear. As for character builds, experiment with mixing different abilities to create versatile characters. And don’t forget to customize your grid to suit your playstyle! Happy exploring!