Professional graphic recorders earn thousands per day, but you can improve your own memory retention (free of charge) by using similar strategies in your own life. Nitya Wakhlu's suggestions:

Listen actively. 
Filter information, boiling the speaker's presentation down to the key points. Look for patterns and connections. Focus on the bigger picture, rather than getting caught up in minutae.
Try brain mapping. 
When you're taking written notes, add a few pictures to illustrate your points. It will help you retain the information in the moment, and the pictures will trigger your memory when reviewing notes.

Learn to draw efficiently. 
Focus on good visual representations that will help you remember key ideas. Don't worry about making the images pretty.

Practice. 
Listen to things that inspire you and make small visual notes in a notebook. Put the finished product up on your wall as a constant reminder of the takeaway points.

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http://www.oregonlive.com/living/index.ssf/2012/04/portland_graphic_recorder_maps.html