The process of evaluating sources is the same you would do if you were going to do an experiment - you would need to know something about an area in order to propose a hypothesis as a possible explanation of what you know. Find Internet sources.
Scholarly journals look serious and sober.
May contain graphs, tables and charts but are short on glossy pictures. Sources are always cited in form of footnotes or bibliography. Are written by a scholar or researcher in the field. Uses the language of the discipline - assumes the reader knows enough to understand the terminology. Main purpose is to communicate results of original research.