I benefitted from a lot of books on how to learn that were written in the 1950s and 1960s. I somehow found them, studied then, and collected my collection of learning tools. I realized that I haven't paid that forward, helping others by sharing what I know on how to learn. This is my contribution, so that others, perhaps younger people, looking for this information can learn it. This article is about learning from textbooks.
Textbooks are not novels, so one shouldn't read them like that. They are a learning tool, and we should read them in a different way.
Get a pen or a pencil, and notebook. Sit down on a desk, and open your textbook. As you read, you should take notes. What kind of notes should you take?
Start with the chapter name. Write down the name of the first section. Look for definitions, formulas, and diagrams. You should write those by hand, as they appear in the text. Use some indentation from the title, so that one can easily see what notes go with what section. Once you reach a new section, start another title and do it again.
As you read through the chapter, you will find out that you are creating your own outline. This will help you when you need to review the chapter if you need to take an exam on the subject.
If at any point you have a question, write it down in your notes. Mark it with a star. Keep reading. Sometimes your question will have an answer just belowin the text. Once you find it, go back to that place in your notes and write the answer there. Sometimes there are no answers, those unanswered questions become the guide to do further research or as a list of questions to ask your instructor.
Once you are done with the outline, check the table of contents in the book for that chapter. See if it matches it. Go back and add missing sections. Once you have read the chapter, the table of contents works as a summary for the content.
Pay special attention to learning goals, if your text have them. Go back and see if you can answer those with your own words. If not, go back in the text and reread the parts that would give you the answer.
You must write the notes by hand. Even if your handwritting is horrible. The point of writing them by hand is to help you learn the material. Writing by hand slows your reading down; it helps you to meditate on the content as you write it down. Trying to go fast leads to not learning the concepts. Going slower is, ironically, going fast.
So don't take pictures. Don't use transcribing LLMs to give you summaries. You need to write them by hand.
Personally, just writing them down is enough for me to learn it. I barely ever looked at my notes again. But it can be different with different people.
Once you are done with a chapter, write a summary. Or go tell a relative or friend what you have learned. Try to teach them. You will probably get to some point where you can't explain some detail. That is good. This tells you where the missing areas are in your learning. Go back and review that section until you can explain it successfully.
If the subject allows it, make diagrams by hand. Diagrams are visual summaries. One can make diagrams for math, chemistry, engineering, grammar, history, sociology, etc. One can make diagrams of most things, but sometimes you can't. That is fine. Still try. See if others can understand the subject from your diagrams. Adjust them if necessary.
You will run into topics that are poorly explained in your textbook. So use other textbooks. Find them in the library or older editions from other authors.
When using supplementary textbooks, you don't have to read the full chapter. You already know the bulk of the content. Go straight to the section where your textbook didn't cover correctly. Go back and forth to see what one author says versus the other one.
Once you have answers, add them to your notes.
We have an artificial urgency to learn things quickly. It feels good; we feel competent; others will admire us for it. It is trap.
The best learning is done slowly. When you go slow, you will master the subject. The faster you try to go, the less retention you will have.
If you are taking a class, you are limited in how slow you can go. But strike to go as slow as your course allows it.
As an adult, reading a section for 10 minutes a day on a new subject has resulted in better retention than when I spent two hours straight, speed reading through a text.