From Creative Commons' Best Practices for Attribution (linked above):
"A good rule of thumb is to use the acronym TASL, which stands for Title, Author, Source, License.
Title - What is the name of the material?
- If a title was provided for the material, include it. Sometimes a title is not provided; in that case, don't worry about it.
Author - Who owns the material?
- Name the author or authors of the material in question. Sometimes, the licensor may want you to give credit to some other entity, like a company or pseudonym. In rare cases, the licensor may not want to be attributed at all. In all of these cases, just do what they request.
Source - Where can I find it?
- Since you somehow accessed the material, you know where to find it. Provide the source of the material so others can, too. Since we live in the age of the Internet, this is usually a URL or hyperlink where the material resides.
License - How can I use it?
- You are obviously using the material for free thanks to the CC license, so make note of it. Don't just say the material is Creative Commons, because that says nothing about how the material can actually be used. Remember that there are six different CC licenses; which one is the material under? Name and provide a link to it, eg. http://creativecommons.org/licenses/by/4.0/ for CC BY.
- → If the licensor included a license notice with more information, include that as well.
Lastly, is there anything else I should know before I use it?
- When you accessed the material originally did it come with any copyright notices; a notice that refers to the disclaimer of warranties; or a notice of previous modifications? (That was a mouthful!) Because that kind of legal mumbo jumbo is actually pretty important to potential users of the material. So best practice is to just retain all of that stuff by copying and pasting such notices into your attribution. Don't make it anymore complicated than it is -- just pass on any info you think is important.
- → Regarding modifications: Don't forget to note if you modified the work yourself (example). If you are at the point where you are creating and licensing derivative works (example), see Marking your work with a CC license.
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."
The above text is licensed to the public under a Creative Commons Attribution 4.0 license.