One of the often quoted barriers to the adoption of open educational resources (OER) is the difficulty of searching for them in a reliable way. Below is a nice infographic that describes a service I use regularly, in particular for finding photos to use on this blog, namely CCSearch. Here you can search for Creative Commons material in the most common repositories such as Flickr, Google Images, Fotopedia and Wikimedia Commons for photos or Jamendo and SoundCloud for music.
Another tactic is to make an advanced Google search but that requires good information retrieval skills to get all the right search criteria. My colleagues at the Blekinge Institute of Technology here in south-east Sweden have formulated an excellent Google search for teachers that is open for all and that searches only for OER.
Try it at OER@BTH.