I think you have practice 800 alot, now you should start solving some 900-1000.

900-1000 or even higher. If they are too hard to you, try with editorials.

Make virtual contests, check the editorial later for the exercises that you did not know how to solve. The difficulty of these problems should not be greater than 1400. (as you improve, you raise this limit)

Spend time practicing and you will see results, good luck ;)