Click to proceed to Flickr's advanced search page
Scroll down and check the box to "Only search within Creative Commons-licensed content"
If you're planning on editing your photos (to stitch them together, to change the colors, to make collages, etc.), make sure you also check the box to "Find content to modify, adapt, or build upon"
When you're looking at your results, we also suggest that you sort by "Interesting" to see some different options that have been tagged, commented on, favorited, and viewed a lot.
Click to proceed to Google Image Search
Use Google Image Search.
Run your search using subject keywords.
When looking at the results page, click on the Search Tools button.
Then select the Usage Rights drop-down list. Select the appropriate option.
Think about different ways you can express information visually: do you have statistics or other data that could be represented in a chart, graph, or table? How might you use maps to plot or contextualize information? What about an infographic, timeline, or wordle?