Well, not just IRSA tools, but mostly IRSA tools...

Most coherent, developed, tested materials

Movie (11:09) on making 3-color images using IRSA's Finder Chart, ds9, and IRSA Viewer -- Dr. Luisa Rebull (2017 .. note that the tools have changed since this movie was made!)
How can I make a color composite image using Spitzer and/or other data? - vintage wiki materials (look at history to see who/when edited it)
Constructing 3-color astronomical images (using IRSA) online classroom-tested lab, from Jimmy Newland
Pencil Code labs on making color images (uses web-based coding) (alumna Wendy Curtis writes of the "Recoloring Universe" portion: "It took my class about 90 minutes altogether and my high schoolers were able to work very independently on it.")

Other important CoolWiki pages