Note-taking helps to filter a large amount of information to find the key ideas and compress them into a format that can easily be returned to later. Notes are used to study, to practice recall and to self-test. 

Note taking while in a lecture or while reading a textbook can keep you focused and engaged. Processing and filtering the information presented is the first step to committing it into memory.

Notes can then be used to study from, so that you are reading a high-yield summary rather than going back to the original source material constantly.

Notes can also be used to write your own questions and flashcards, which will allow you to really lock concepts in your memory.

The simplest tools for note-taking are a pen and paper. If handwriting notes, you may want to invest in a book to keep everything together. This can be further expanded with coloured pens, glued-in images, crayons, glitter or whatever it takes to help you learn.

If taking notes digitally, laptop computers are portable, and offer more usability than mobile devices. Tablets are widely used for note-taking, and these devices are becoming easier to use in terms of typing, editing and multitasking. Digital paper devices are also becoming more popular as they simulate hand-writing notes but with additional features such as text recognition and the ability to categorise notes.

There are many note-taking apps available for Windows, OSX, iOS and Android, each with different features and at different price points. Some of the most commonly used note-taking apps are Microsoft OneNote, Evernote, Google Keep, Notion and Bear.

If possible - and particularly while taking notes digitally - try to have a central repository of notes and continually add to it, rather than having a separate note for each lecture or study section. This will mean that you can build on what you learned previously, and just have one place to go to review a concept - rather than many separate notes with overlap. Separate these by body system, specialty, chapter or whatever makes most sense.

Having said that, don't just read your notes over and over again hoping to remember more with each repetition. A study in Science magazine showed that students who practiced repeated study material performed inferiorly to those who underwent repeated testing.

Therefore, the best way to put your notes to work is by using them to promote recall. If you use the outline note-taking method (i.e. you use a lot of dot points) then consider trying the split-page or Cornell methods detailed below. Further to this, use your notes to write questions and flashcards that you can then use to test yourself with

When writing digital notes there is a tendency to copy lecture slides verbatim, and copy and paste information 'to read later'. As a result, digital notes can be more shallow. Conversely, handwritten notes rely on summarising and synthesising information.

When writing handwritten notes, consider using different colours to represent different types of information.

This is thought to be due to the fact that working harder to interpret text requires more mental focus than text that is easy to read, meaning that more active attention is used. 

Therefore, it may be worth using a font that you hate, such as Comic Sans, Bodoni MT, Haettenschweiler or Monotype Corsiva.

Outlining is the most commonly used note-taking method. This involves titles, dots points and numbered lists. Indenting is used to demonstrate relationships between pieces of information. If structured and written well, outlines can condense a large amount of information into summarised form with a clear hierarchy.

Outlines can be difficult to use if you're adding a lot of images or formulas, or if you're directly comparing multiple pieces of information.

Writing on or around lecture slides is the most efficient method of note-taking. Notes can be handwritten or added digitally. Many lecturers provide slides with space next to them to write on, or you can set this up in Powerpoint.

However, you may not always have access to the lecture slides. You will also quickly have a buildup of printed or digital slides to go through that you can't necessarily build on - your notes will become a snapshot of that particular lecture. If you're likely to go back and revisit it then that's fine, but if you'd like to build notes up and easily access them then this is not the best method.

Creating a table can be useful a useful way of categorising information, or comparing and contrasting ideas. They are great for memorising information because they elucidate the relationships between concepts.

Tables are difficult to make quickly, and are more useful when you're in your study time. They require understanding of the overarching structure of the content as they are relatively inflexible once the rows and columns are labelled.

Mind maps are a way of relating ideas to each other. Lines are drawn between concepts and subconcepts to demonstrate hierarchy of the information. It mimics the way that the brain works - we process information and memories in terms of relationships between ideas, rather than sequentially.

Mindmapping is at least non-inferior to standard note taking: in a study of 131 medical students attempting to remember a text passage, there was no significant difference between the group that learned by standard note-taking and the group that learned by drawing mind maps.

This method is useful for understanding complex topics, and maps can easily be changed, edited and built upon. Maps can become difficult to use when it is unclear from a lecture or text how the concepts presented relate to each other. Overly bulky mind maps can be complicated and difficult to follow.

Note-taking using the flow method is a way of simplifying and processing information then representing it visually. Flow-based notes are essentially a transcription of your mental image on a topic, rather than a hierarchical or categorised system.

This method allows for learning during lectures rather than just writing down what is said, and requires the most active processing. While writing flow-based notes, try to focus on listening and paying attention, writing down only the key concepts in as few words as possible. Draw arrows to connect related ideas.

Flow-based note taking highlights important concepts in realtime while minimising irrelevant details. This can allow you to avoid mindless copying that can occur with hierarchical note taking techniques such as outlines or mind maps.

On the other hand, flow-based notes are often messier and miss details - you may need to go back and relisten to the lecture if a detail isn't written down.

The split page method is similar to the outline method, but uses keywords and questions to aid with recall. This is done by drawing a vertical line down a piece of paper (or using a table of writing notes digitally.

On the right side, outlined notes are written in a concise way, including key concepts and ideas. On the left side, keywords and questions are written that directly relate to the information next to them. Keywords are used as cues to stimulate recall later on, while questions can be used to test yourself on the content.

The Cornell method is similar but slightly more involved that the split page method.

A piece of paper is divided into three sections. On the write side, an outline is written that explains the key ideas in a concise way. On the left side, keywords and questions are written that stimulate recall. At the bottom is a brief summary of the content on the page.

Once the notes, keywords and summary are written. Look at the keywords and state what you remember from the content. Try to reflect on how the information links with other similar concepts.

We will include this highly complicated method for completion. German for 'slip-box', the Zettelkasten method makes use of a system of index cards which allow ideas to be connected together. Links between related ideas allow new insights, which can reportedly be used to improve thinking.

Think of the technique as your own personal Wikipedia - you create links between cards that helps you to understand how the ideas fit together.

The method was created by Niklas Luhmann, a German sociologist; he used the technique to write 70 books and 500 articles over 30 years.

The system is very complex, and there are many other resources online for learning about it.

Try using a few different note-taking techniques through the course of your study and find what works for you in terms of style, ease and recall. You may find that a combination of a few methods works - outlines for the heirarchical information, tables for categorical information, and flowcharts for processes.