General tips for your search
Search for the CC license or tool
There are many, many, many repositories out there that have openly licensed images. Some of them don’t use standard CC licenses, but rather use their Terms of Service (ToS). These terms and conditions are similar to what CC licenses offer. However, they are not compatible with the CC licenses, so you need to evaluate carefully whether to incorporate them in your work or not.
Additionally, you might also want to use resources that are licensed under the latest version of the CC licenses (version 4.0).
Use search filters
To get the most out of all the resources that are available under open licenses, you need to make use of the extensive search filters that repositories of content (images, videos, sound) offer. In some websites it’s easier than in others, but in general most of these repositories offer some type of search filter. In some repositories, like Wikimedia Commons, all the content you find will allow for re-use, so you will never find Non Commercial or Non Derivatives licensed content. But if you’re searching on a website like Flickr, using the search filter is crucial to only search for content you can reuse.
Pro Tip: Build your personal list of websites for finding openly licensed content. Different open-licensed content sites have different strengths and weaknesses. Focus on the ones best for your content needs.
Check the quality of the resources
Depending on which repository you are searching for content, the quality of the resources might be fit for some purposes but not for others (for example, they might be adequate for posting on the web but not for printing). Normally, most repositories will allow you to filter also for quality.
Searching in languages other than English
Some multimedia platforms and repositories support multilinguality, while others don’t. Of course, you will find out soon enough the moment you try to do a search on a language other than English and don’t get any results. That’s when no multilinguality is supported. However, in some cases what can happen is that multilinguality is supported only to a certain extent. For example, look how different the results are on Flickr if you search for “mujer”, “wanita” and “woman” (the search doesn’t have any filters by license). The same happens in most repositories, so if you don’t find what you’re searching for, try using keywords in another language, if you happen to speak more than one language.