don’t use too much material (ie, appropriate amounts)
use for critique
use for giving context
use for launching discussion
use for mashups
always give credit to sources

Read or download the report and the code at the American University website.  Study.  And get to work.  The code doesn’t carve out new law but it does explain what may not be clear to many–that you can use copyrighted material and that the fair use doctrine will cover you under many circumstances if, for example,  you get a takedown notice.