1. Learning by heart means learning with questions.
2. Learn purposefully and selectively.
3. Studying attentively means learning to think, thinking in reading, reading in thinking, pursuing ideas in reading, harvesting ideas in reading and enriching ideas in reading. Learning without thinking is useless, thinking without learning is dangerous, and reading itself should be a good way of learning. As long as you think, you get something, but if you don't think, you get nothing.