In his "Telling the Right Stories with Data Visualizations" webinar, Noah Iliinsky shared a lot of great tips for making effective visualizations. Here are a few:

• Find Iliinsky's chart about using visual encodings on his blog, http://complexdiagrams.com/

• Try these sources for data for practicing visualizations: buzzdata.com, infochimps.com, and data.gov.

• Tableau is a great tool for visual analytics that has good defaults. You can quickly iterate on graphics in Tableau. There's a free version, tableau public, but it can't be stored locally. Tableau only works in Windows, however.

• Omnigraffle is great for diagrams, charts and hierarchies.

• When you're not sure what story your data shows, seek trends, gaps and outliers, and explore.

• Selecting the correct axes for displaying data is critical, and most people don't spend enough time on it.