Since you can book dining 180 days in advance, lots of the most popular table service spots are solidly booked pretty far out. That's especially true for the extremely popular character meals. You can cross your fingers and keep trying (in case there's a cancellation)... Good luck.
Welcome to Disney vacation planning where you must book at least 3 months in advance if you want a sit down character meal.
We booked in September last year and while I managed to book some popular meals they weren't at the best times, I'm sure those fill up and by the time you get closer nothing is available...and we were there during a very slow time.