At your stage of learning (early), I suggest that you focus on doing exercises based on the texts you read. I assume that most of them are textbooks and hopefully they include many exercises.
In CS, you can write a lot of programs at this stage to solidify your learning.
Another option is to take notes and, especially, make notes on the questions you have that you can get advice on from a professor. I find it useful to use index cards for such notes. Initially write on one side so you can revisit the idea on a card and update it.
But reading is, in itself, too passive for deep learning and building insight. You have to move to some form of active learning. Exercises and sample programs are good for this.
If you are reading books that go beyond texts, one way is to form a small study group. Even two people is enough, three probably better (best?). Read the article and discuss it with your group. Others may understand some points better than yourself and you can help them understand other points perhaps. Again, take notes to capture insights. Ask someone knowledgeable (the professor) for things left unresolved.