TIP #1: SEED ARTICLE
Begin your research with a "seed article" - an article that strongly supports your research topic. Then use a citation database to follow the studies published by finding articles which have cited that article, either because they support it or because they disagree with it.
TIP #2: SNOWBALLING
Snowballing is the process where researchers will begin with a select number of articles they have identified relevant/strongly supports their topic and then search each articles' references reviewing the studies cited to determine if they are relevant to your research.
BONUS POINTS: This process also helps identify key highly cited authors within a topic to help establish the "experts" in the field.
Begin by constructing a focused research question to help you then convert it into an effective search strategy.
What is a literature review?
A literature review is a comprehensive and up-to-date overview of published information on a subject area. Conducting a literature review demands a careful examination of a body of literature that has been published that helps answer your research question (See PICO). Literature reviewed includes scholarly journals, scholarly books, authoritative databases, primary sources and grey literature.
A literature review attempts to answer the following:
The Study Design 101 tutorial help you understand the different kinds of studies and each studies strengths and weaknesses.