How consistent is your CR score, relative to other sections?

For the longest time, Critical Reading had always been my weakest section. From 7th to 10th grade, my score always stagnated at the 560-610 range, then it went up to 690 on the May SAT. I took the October SAT, and I was shocked to see that it went up to 770, higher than I ever thought possible. I’m planning on taking the January SAT to increase my single-sitting to 2300+, but I’m afraid my reading score will decrease, especially since this was the first and only time I’ve done so well, and that my math score somehow dropped almost 100 points…how can I prepare to maintain (or possibly increase) my score?