My first rule of thumb is: develop the concept first, then worry about tools.
I believe the software question is misplaced. One should never allow tools to get in the way of one's imagination.
Like an artist, I carry a sketchbook in which I draw many versions of charts for each data set I come across. Once I see each version, I can better judge what works, and what doesn't. As I sketch, I'll sometimes find insights in the data I haven't notice before, which will prompt another round of sketches. Until I finalize the concept, I don't think about software. Until this point, it's as primitive as it gets.
What has all these got to do with the Madonna wall advertisement? Notice the artists standing on the crane in the lower left corner. I was walking in New York while thinking about this post, and thought what a perfect example of sketching, or developing the concept. The artists weren't deciding what and how to paint the ad while the crane scaled the ten-storey building; they already had it sketched out, both on paper and on the wall itself. Here is the blown-up image of Madonna's unfinished hand. The sketchmarks were clearly visible. So next time you make a chart, try making sketches first!