Making Your Voice Heard: A Media Toolkit for Youth is designed to help young people understand how the news industry works (different roles), why youth stereotyping happens and how they can access media to get positive youth voices and stories heard.
Mozilla has created a framework for entry-level web literacy & 21st Century skills. Explore the map by selecting what you want to learn more about: Participate, Write or Read. Each of the subsections provides definitions and teaching resources.
This page from the Media Literacy Now website has an explanation of media literacy with a short animated video. There is a second video that has high school students describing why media literacy is important to them.