Use a matrix
Allows you to stay organized as you record features of the studies you include. Here is a good example of a matrix (from Bowdoin College).
Use the Zotero citation manager
As you search for articles, gather and organize metadata with Zotero. This means you don't have to scramble to track down citation information later.
PLOS guidance
Ten simple rules for writing a literature review
A good article from PLOS (Public Library of Science, an important journal) which gives good advice on how to conduct a literature review.
APA guidance
Literature search tips and tricks: techniques for effectively using Google Scholar and PsycINFO from the American Psychological Association.