Pulling together a good lit review is not usually a linear process—authors will often need to go back and check the literature while developing their ideas and to stay up to date on the latest updates/breakthroughs in a particular field. This also means you should not try writing your literature review in one sitting, but constantly working on it before, during, and even after your study is complete.
Remember, the key is to summarize and synthesize.
Source: Kevin H. (2018) How to write a literature review. Wordvice. https://wordvice.com/how-to-write-a-literature-review/.
A systematic review attempts to collate all empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question. The key characteristics of a systematic review are:
Source: Brown University Library. (2020). Systematic and literature reviews. https://libguides.brown.edu/Reviews/types