Hi,
my advice to every new PhD student starting to read for the background of their topic is the following:
1. use a bibliography program, like Mendeley (free) to organise your references
2. Divide references in categories
3. keep detailed notes of each paper in OneNote (Word)
4. Create an excel database of the results
I used an excel matrix with the following categories:
Author, Year | Sample (Number of responses) | Method | Results (mean, min, max) | comments
These tables (or graphs) can be put in your thesis
5. Compare papers quantitatively - Meta-analysis. What other researchers found? Why do some people disagree? Do the methods affect the results? Where is the gap?
I was very organised from the beginning, and writing all the way (since day one). I managed to publish a meta-analysis paper by the end of the first year. Of course, I had to edit again and again until the final version.
It takes A LOT of time, but lit review is one of the hardest chapters, and when you have results it is very easy to compare with previous research. You can critically analyse if you expected these results or not (so it will help you in your discussion too)
Good luck!