Try understanding things yourself. When you read about a topic, apply your brain and try to understand the logic behind everything. Even if you don't succeed in this, it's okay. You have teachers for explanations, and there are many good videos online nowadays which can help you. But what matters the most is, you should try by yourself to figure out the logic behind every concept. Start by today itself, doesn't matter how much you can think, but you'll surely improve your thinking skills slowly. You just need to start thinking about everything. And you can do it!
