Read your section of text, whether it comes from a blog, magazine, book, your own writing or another source. As you read, mark any key thoughts, ideas or subjects with a highlighter. Write these down on a separate piece of paper.
Review your keywords and determine what you will use as your main subject or the center of your mind map. On a clean sheet of paper, write that main subject in the center in pencil. Now draw lines out from there and write the keyword next to it. Don't worry if you have a lot of lines extending from the main subject, this is how mind mapping works.
Re-read the article paying attention to the keywords you've already highlighted or underlined. Using a different colored highlighter than you used for the keywords, look for main ideas, thoughts or concepts related to each keyword that you had on the list. Go through the text completely and identify them all.
Draw lines on your mind map in pencil that extend from each keyword you've already drawn. These will be where you'll write your newly underlined words or phrases. You may find it helpful to check them off as you work through the text, ensuring you don't miss any or write them incorrectly. Your mind map should now have the core subject or idea in the middle, with multiple lines extending out that have the keywords written on them. Extending from those keywords should be additional lines that have main ideas, thoughts or concepts that relate to each of the keywords.
Review your mind map when it is complete and then re-read the text closely. When you are satisfied that you've gotten all the key points on your map you can now complete it with illustrations, colored markers or however you'd like to finish it. The text you originally had is now converted to a mind map that should convey the same ideas as the text in an entirely different format.