Unsure what a scholarly journal article looks like? This Interactive tutorial identifies sections that should appear in a scholarly journal article.
Where you should search depends upon your topic. Best database for religion is ATLA Religion Database.
If you want to focus on the sociological aspects of religion, try Social Sciences Full Text.
Searching for the political aspects of a religion? Political Science Complete is where you should begin.
Interested in the history of religion? Try America: History and Life, a database that covers American history.
Image Source: Eanger Irving Couse. Native American Smoke Ceremony. Public domain. Wikimedia Commons.
Scholarship on major religions, faiths, denominations presented in many different languages. Includes journal articles, books, reviews and essays.
Important topics covered include: Biblical Studies, World Religions, Church History, and Religion in Social Issues.
Covers the history and culture of the United States and Canada from prehistory to the present.
Largest social sciences database, providing access to over 4,300 social sciences journal titles.
Subjects covered include: anthropology, economics, geography, law, political science, psychology, sociology.
Access over 12,000 regional, national, and international full-text news sources.
Almost all of the library's databases will allow you to limit to academic/scholarly, or peer-reviewed journals. Limiting to academic/scholarly, however, is imperfect: You'll also retrieve professional journals. Some professors consider these scholarly; others don't.
Ask your professor to clarify this.
How can you tell what it is you found? You'll need to look for clues. None of these clues may be consistently applied--taken together, however, they can get you close.
Still unsure? Check Ulrich's Periodicals Directory for the definitive word on whether your source is scholarly or general.
Image source: Syker Fotograf. GNU GPL. Wikimedia Commons.