A good literature review should avoid the temptation of stressing the importance of a particular research program.
The fact that a researcher is undertaking the research program speaks for its importance, and an educated reader may well be insulted that they are not allowed to judge the importance for themselves.
It is usually presented as a distinct section of a graduate thesis or dissertation.
The purpose of a literature review is to give an accurate and complete accounting of the current state of knowledge for whichever research question is being addressed.
It is an essential feature of scholarship because without it the reader cannot judge whether the author is well-informed or whether the work that is being presented is novel and original.
Most often a literature review is a section of a scholarly article or book (usually toward the beginning) which summarizes and evaluates previous scholarship.
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.
It’s challenging to judge the credibility of an online paper.
It can be helpful to structure your internet research as if it were conducted on paper.