It pulls the previous research together, and explains how it connects to the research proposed by the current paper.
All sides of an argument must be clearly explained, to avoid bias, and areas of agreement and disagreement should be highlighted.
A literature review is likewise not a collection of quotes and paraphrasing from other sources.
A good literature review should critically evaluate the quality and findings of the research.
Bookmark papers, which may be relevant, in one folder and make another subfolder for a ‘shortlist.’ Conducting a good literature review takes patience and is a matter of practice.
Take solace that even the best scientists can fall into the trap of using poor evidence. If your research program is well constructed, a less-than-perfect literature review will not affect the results.
As a general rule, especially for a longer review, each paragraph should address one point, and present and evaluate all of the available evidence, from all possible differing points of view.
Evaluating the credibility of sources is one of the most difficult aspects of a literature review, especially with the ease of finding information on the internet.
The only real way to evaluate is through experience, but there are luckily a few tricks for evaluating information quickly and accurately. Google does not distinguish or judge the quality of results, only how search engine friendly a paper is.
This is why it is still good practice to begin research in an academic library.