I recently spoke on The Marketer Webinar Series on how to approach visualising data. You can see the full webinar here. It unfortunately sits behind a registration wall so if you just want to browse the slides you can do so below. My notes are also available on the slideshare site (they sit in the notes on each slide, which isn’t that easily discoverable) if you want to delve deeper.
http://www.slideshare.net/riazkanani/visualisation-science-or-art