Write the subject or main idea of the lecture, such as “Advanced Pyrotechnics,” in the center of your piece of paper and draw a circle around it. The bigger the piece of paper you use, the better. Of course, you do not always have much room to write during these occasions.
Identify each major topic of the talk as it comes along. Draw a line for each of these topics that radiates out from the central idea and label each of the lines with the topic.
Note important facts and sub-topics for each of the topics during the talk, drawing additional lines for each of these new sub-topics.
Continue expanding on each sub-topic until the speaker moves on to the next subject, and then move on to draw a new topic line for the next one. Work your way through each of the sub-topics until you write down everything you need to take away from the talk.
Color code branches or ideas after the talk, if you like, to set them apart visually.