You can also use linear notes to record new words. Write the topic at the top of the page and then record related words below. For an example of linear notes see source links.
Record the meaning of each new word. You can draw a picture, write a definition, write a similar word, or, if it is a foreign word, you can write a translation.
Keep adding new words. Add new words to your mind maps and to your linear notes regularly. Create new pages for new groups of words.
Review your words frequently. It is easy to forget what you have learnt if you don't revise it. Try to look at your notes at least every week.
Use lots of colour in your notes to make your vocabulary easier to remember.