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. Note: You can learn how to mark your own material with a CC license.
Here is a photo. Following it are some examples of how people might attribute it.
Title? "Creative Commons 10th Birthday Celebration San Francisco"
Author? "tvol" - linked to his profile page
Source? "Creative Commons 10th Birthday Celebration San Francisco" - linked to original Flickr page
Note: If you're at a point where you are licensing derivative works, go to Marking your work with a CC license.
You can visit the Saylor.org Introduction to Statistics course page to see how they marked it up directly.
A good rule of thumb is to use the acronym ">TASL, which stands for Title, Author, Source, License.
What is the name of the material?
Who owns the material?
Where can I find it?
How can I use it?
Lastly, is there anything else I should know before I use it?
These best practices are based on actual CC license requirements. Noting the title is a requirement of all CC licenses version 3.0 or earlier, optional for 4.0. Noting the author, source, license, and retaining any extra notices is a requirement of all CC licenses. See Devil in the details.
If you have any doubts or questions, you can read the complete attribution requirements which are spelled out in detail in the legal code of every CC license, eg. http://creativecommons.org/licenses/by/4.0/legalcode#s3a. This chart compares the detailed requirements across all versions of CC licenses.
The license tells you to be reasonable:
There is no one right way; just make sure your attribution is reasonable and suited to the medium you're working with. That being said, you still have to include attribution requirements somehow, even if it's just a link to an About page that has that info. (More on different mediums below.)
As stated above, best practices for attribution apply as reasonable to the medium you're working with. For media such as offline materials, video, audio, and images, consider:
CC BY Attribution
This license lets others distribute, remix, tweak, and build upon your work, even commercially, as long as they credit you for the original creation. This is the most accommodating of licenses offered. Recommended for maximum dissemination and use of licensed materials.
This license lets others remix, tweak, and build upon your work even for commercial purposes, as long as they credit you and license their new creations under identical terms. This license is often compared to “copyleft” free and open-source software licenses. All new works based on yours will carry the same license, so any derivatives will also allow commercial use. This is the license used by Wikipedia and is recommended for materials that would benefit from incorporating content from Wikipedia and similarly licensed projects.
This license is the most restrictive of our six main licenses, only allowing others to download your works and share them with others as long as they credit you, but they can’t change them in any way or use them commercially.
“About The Licenses.” Creative Commons creativecommons.org/licenses/.