Staff and students in your area can be good sources of ideas about where to look for relevant literature.
They may already have copies of articles that you can work with.
It would be safer and probably more realistic to say that your research will ‘address a gap’, rather than that it will ‘fill a gap’.
When readers come to your assignment, dissertation, or thesis, they will not just assume that your research or analysis is a good idea; they will want to be persuaded that it is relevant and that it was worth doing.
You can then begin your process of evaluating the quality and relevance of what you read, and this can guide you to more focussed further reading. It can give you a degree of control, in what can feel like an overwhelming and uncontrollable stage of the research process.
Taylor and Procter of The University of Toronto have some useful suggested questions to ask yourself at the beginning of your reading: can add other questions of your own to focus the search, for example: What time period am I interested in? Searching electronic databases is probably the quickest way to access a lot of material.
The term ‘synthesis’ refers to the bringing together of material from different sources, and the creation of an integrated whole.
In this case the ‘whole’ will be your structured review of relevant work, and your coherent argument for the study that you are doing.
This will then provide you with a long reference list, and some evaluation of the references it contains.
No electronic literature search can be 100% comprehensive, as the match between search terms and the content of articles will never be perfect.