Understand the rules before you begin.

Before you get started on your video, view this video to learn the basics of following Copyright law.
YouTube Copyright School (4:30)
View this video to better understand how to use content licensed under creative commons.
What is Creative Commons? (3:19)

Use these resources along the way.

Flickr
Flickr allows you to set a filter so that you only search creative commons licenses. Make sure you select this option on the home page.
Google Advanced Image Search
Select "Free to Use or Share" next to usage rights. On the search results page it will say "Labeled for Noncommercial Reuse."
Creative Commons Search Tool
Use this prototype to find images that you can use and remix across several open archives.
A Copyright Friendly Toolkit
Guidelines, categories, and tools to consider that will help you as you create, contribute to, and enrich our shared culture
YouTube Audio Library
Freesound Freesound aims to create a huge collaborative database of audio snippets, samples, recordings, bleeps, ... released under Creative Commons licenses that allow their reuse.
Pixabay All images and videos on Pixabay are released free of copyrights under Creative Commons CC0. You may download, modify, distribute, and use them royalty free for anything you like, even in commercial applications. Attribution is not required.
Best Practices for Attribution You can use CC-licensed materials as long as you follow the license conditions. One condition of all CC licenses is attribution. Here are some good (and not so good) examples of attribution.

Getting started with WeVideo

WeVideo Tutorials: Projects (1:30)
WeVideo Tutorials: Dashboard Overview (1:44)
WeVideo Tutorials: Collaborative Projects (1:18)
WeVideo Tutorial: Storyboard Editing Mode (1:22)

Customizing Your WeVideo

How do I add text to my video?
Learn how to add freeform text graphics anywhere in your video or edit predefined Theme text graphics that go with the Theme look and feel.

Rubric
Book Trailer Rubric