I want to practice solving 2200-2400 rating problems, and I want to rely on guides as less as possible. But every time I am stuck on one problem, I have to worry about whether I am missing an observation or I just need to learn a new topic to solve this problem. I want to know and learn the topics and problem solving techniques that are common in problems of this range, so that the chances of me missing a topic when trying to solve a problem is as low as possible. What are the common topics that I need to learn