Is this a first edition of this publication or not? Further editions indicate a source has been revised and updated to reflect changes in knowledge, include omissions, and harmonize with its intended reader's needs. Also, many printings or editions may indicate that the work has become a standard source in the area and is reliable. If you are using a Web source, do the pages indicate revision dates?
Note the publisher. If the source is published by a university press, it is likely to be scholarly. Although the fact that the publisher is reputable does not necessarily guarantee quality, it does show that the publisher may have high regard for the source being published.
Is this a scholarly or a popular journal? This distinction is important because it indicates different levels of complexity in conveying ideas.
***author credit to Research & Learning Services, Olin Library, Cornell University LibraryIthaca, NY, USA