►When designing a Literature Review for any topic it is useful to establish a meta-narrative for the project. This forces a clear understanding of what kind of Review you are conducting. What is a meta-narrative in this context? Try phrasing your topic in terms of a story you are telling. For example if you are researching the impact of mobile diagnostic units on rates of TB in a country in Africa. You might compose your meta-narrative as "if a school child in ____ has been exposed to TB, how much does it affect her possibilities for a healthy life if a mobile diagnostic unit is available in her village?" The pertinent phrase here is how much, because research will concern itself with a comparison of a base line rate of TB cases with the rate where mobile diagnostics have been available.
►Highlight how you are going to weight articles you discover in terms of their pertinence to your narrative.
►How will you know when you have covered the entire literature on a topic? When you start to get recursive results from your searches.
Once the citations you import from an index in to your citation manager start to cite the articles you have already included in your review, then you have covered the topic.