Few databases allow you to limit your searches to literature reviews:
PAIS --> Select Literature Review from the Document type box
Worldwide Political Science Abstracts --> Select Literature Review for the Document type box
The goal of the literature review is to show that you understand the 'bigger picture' and can put your research and recommendations in context of others working in the field.
Try to find the most recent articles that deal with your topic; many of them will summarize the prior literature in the area, saving you valuable time.
Search for key authors who have contributed to the topic. It can be overwhelming. Just find the literature mist relevant to your topic. You can't find/use everything.
Use current sources - include chronological, thematic, methodological.
Use quotes sparingly and keep your own voice.
Remember to attiribute even if you paraphraze.