Read the entire page before taking any notes. Underline any passages or paragraphs that strike you as being particularly relevant or important.
Read the page again and make notes in the side margins. Your second reading can be close or a little less close, depending on how well you understood the text the first time. This time, when reading, make notes in the margins about the argument being made or the points being raised -- what are they, what do you think about them, what's missing?
Write a brief summary at the bottom of the page based on your margin notes. Do this if the page contains important information. You may not need to do this on every page -- perhaps only every few or every several pages. If you do write a summary at the bottom of the page, you can separate it into two sections. One section can be for the argument or points raised by the author, and the second can be your thoughts and reaction to the material.
Write a chapter-end summary in the margins. At the end of each chapter -- or section, if this is more appropriate for the piece you are reading -- write a brief summary of the most important information contained in that chapter or section. Write out the key points and note why they are important. You may also include a section on your own thoughts and reactions to what you have just read.