Creating data visualizations is a complex process, but it is helpful to be generally familiar with the basic steps. Noah Iliinsky outlines the basic steps that are (or at least should be) common to all visualizations:
For a more detailed explanantion read his post, Four Pillars of Visualization.
There are many sources that describe best practices for visually encoding data, but the one below, from Noah Iliinsky, provides a nice overview of the different graphic variable types.
