Stop writing at the line you drew down the page. This style of note-taking is called the Modified Outline, and it can be used for taking notes while reading a book or listening to a lecture. The area on the other side of the line you made is for taking notes on your notes. After you have finished your reading, read back through your notes, adding anything you think is needed for clarity and completeness. Also, write questions you have about the material and any vocabulary words you find in your reading.
Some people enjoy taking notes with colored felt pens or with different colored ballpoint pens.
If you are a visual learner, using color will help you take better notes. If you are a kinesthetic learner, writing more notes will help you learn, even if you don't always reread the notes you take. If you are an auditory learner, consider taking the extra step of reading your book into a tape recorder, then taking notes when you play back the tape for yourself or read aloud to yourself while taking notes. One quality of a good student is knowing how to read books and find the information you need. The next few activities will lead you in finding information through your reading.