Hey fellow Final Fantasy X explorer! When it comes to sphere grid progression, focus on unlocking key abilities for each character first before branching out. Don’t be afraid to backtrack to grab important nodes. For side quests, be sure to complete the Monster Arena challenges for great rewards. Character builds vary, but consider specializing each character in a specific role to maximize their potential in battles. Experiment with different paths on the sphere grid to find the best fit for your playstyle. Happy exploring!