As you read, you may not yet know for what purpose you might need the notes you take, or if you will need them at all. However, if you are writing an essay, it is helpful to think about what you are looking for as you read, and decide on a few key issues or questions which you need information on. The key aspects to consider in structured note-taking are having a specific aim, flexibility and findability. Note-taking strategies which rely only on marking up the text (book or article) may be unhelpful in the context of reading for an essay (although they may be useful if reading for a seminar or supervision, if you are taking notes to record your response to a text). Using strategies such as highlighting and underlining, or even making notes in the margin, can be risky, as it can become a passive, unthinking process and therefore easy to become unselective and forget what you are looking for. This method is also bound to the structure of the text from which you are making notes, and therefore not flexible, which, if you are writing, may not help your own structure develop (marking up the text may have other uses, for example, aiding skim-reading to establish where any smaller points of interest are located so that they can be returned to later). See the resource How might I manage the process of producing an essay? for more guidance.
Another common strategy is to make notes in a separate place, whether a sheet of paper, notebook or computer file. Students commonly organise their notes by creating a separate set of notes (page, sheet of paper or computer file) for each separate text, and again, your notes, ideas and structure could become dependent on that text. However you could experiment with other, more thematic ways of taking notes. Instead of allocating a sheet of paper or computer file to each separate text you read, you could try deciding in advance what topics, perspectives or questions you need to gather information on, and as you read each text, you record what you find in the appropriate thematic location. This way, your reading and note-taking is structured by your aims, not those of the texts you read.
For an example of thematically organised notes, click here (Essay title: Discuss the power of the eye in Frankenstein).
Non-linear forms of note-taking, such as mind-mapping, may also help you to develop your own structure more clearly. They force you to distance yourself from the original structure of the text and organise the ideas yourself, whereas linear strategies such as bullet points on lined paper can encourage you to recreate the text's structure, not develop your own.
For an example of Mindmap notes, click here (Essay title: Discuss the power of the eye in Frankenstein).
Try out the strategies in your supervision essays; supervisions are a safe space to experiment with different approaches and gain feedback on the way your writing is developing. You could ask your supervisor for specific feedback on this issue or for tips on how to structure your work.