You have access to a variety of sources; however, there is not a definitive best type. The best source depends upon the purpose of your search and the information you need.
For example, if you are looking at current events, you should start with newspapers, Internet sites, and magazines, as they are published quickly and are generally more up-to-date than books. Books, on the other hand, are good sources for historical accounts and analysis of events, as well as more in depth coverage of topics.
Sources available as you conduct research will vary quite a bit in purpose, audience, and reliability. One important distinguishing characteristic is whether a periodical is considered popular or scholarly/academic. You need to learn how to tell them apart as well as determine which type is more appropriate for your information needs.
McMaster Libraries. How Library Stuff Works: Scholarly vs Popular Sources. YouTube. Creative Commons Attribution license (reuse allowed).
Think about the magazines you find in grocery, drug, and book stores. In popular magazines, you generally find lots of advertisements in addition to articles illustrated with several pictures. Popular magazines are written for the general public, usually for entertainment, general information, or keeping up with current events.
Popular magazines are normally written and edited by professional journalists. The authors who write the articles are usually not subject experts, but are expected to have done adequate and appropriate research in preparing the article. The editor has final say on what gets printed in the magazine.
What you might use them for: Finding examples of print advertisements; current interest topics; basic information; entertainment; etc.
Academic/scholarly journals are written for students, faculty and professionals, and contain high quality articles. Research results are generally published in these periodicals, and charts and graphs are common for presenting data. The limited advertising is geared toward the specific audience that read the journal.
Articles in academic/scholarly journals are written by subject experts, as opposed to journalists that write for popular magazines. The editors who make the final decision on what is published also have expertise in the subject area covered by the journal.
What you might use them for: Finding research and/or analysis about various topics and events.
Peer review adds an additional level of reliability. Not only are these articles written by subject experts, they are also reviewed by other subject experts for quality before being accepted for publication.
McMaster Libraries. How Library Stuff Works: Peer Review. YouTube. Creative Commons Attribution license (reuse allowed)
Trade Magazines are usually published by a professional organization for its members and others in the field. (Some trade magazines are also considered academic/scholarly journals.)
Trade Magazines are generally written and edited by practitioners in a field.
What you might use them for: Finding articles about current practice and/or interest in a field.