Learn to differentiate between active and passive note-taking. Active note-taking is the most effective because it helps you create meaning from what you learn. Don't do the hours of passive note-taking only to realise that you have not organised your notes in a way that helps you make meaning from them.  You are less likely to remember things you learn passively. 

What is passive note-taking? It includes:

• underlining or highlighting words 
• cutting and pasting from online documents
• trying to write down everything you hear
• copying slides from the screen
• copying lots of direct quotes rather than putting the ideas in your own words 
• writing notes on everything you read, because you're not sure what will turn out to be important 
• not evaluating or criticising the sources you use, but just accepting them as suitable evidence 

Notice that the above behaviours will be a waste of time because you are collecting and highlighting anything that might be useful without any critical purpose.

Active note-taking includes:

• thinking about what you want to get out of your reading or research before you start
• looking for answers to any questions you may have about the topic
• looking for connections within the topic you're studying
• writing notes mostly in your own words with your own explanation of what something says or means

Notice how active note-taking is a process of critical evaluation and selection, as well as the start of your learning process. 

(Modified from the University of Reading note-taking resources)