It's usually easy to know when you have a piece of scholarly information: it was written by experts on the subject, it underwent a peer review by other experts on the subject, it contains original research, it was published in a scholarly journal.
Similarly, you can usually identify a piece of popular information: it was written by a journalist (or it doesn't list an author at all), the writing is entertaining and informal, there are no references or citations.
However, not all information falls neatly into those two categories. There can be a range of source types between popular and scholarly.
For example, information from websites like The Pew Research Center are an excellent source for statistics and public opinion. Data scientists conduct original research on topics that shape society, analyze the data in an unbiased way, and present the final information in the form of a report.
Here are some examples of sources that do not fall under scholarly or popular but would still be good sources for your research.
When searching the free web, you'll typically encounter the same few website domains. Here's what they mean:
Try library resources first (like books and databases). If you search Google, try these search tips:
use "quotation marks" for phrase searching
-site:.com added to your search will eliminate ALL .com sites in search results
site:.edu (or site:.gov) should ONLY search within the designated domain
Use the SIFT Method to evaluate what you find