The Institute of Medicine's (IOM) Standards for Systematic Reviews make it clear that several things should be in place before you begin. These include:
A multidisciplinary team - at minimum:
Balance on the team is important - as the IOM standards note (pp. 48-49): "...review teams that are too dominated by clinical content experts are more likely to hold preconceived opinions related to the topic of the SR, spend less time conducting the review, and produce lower quality SRs."
A good topic/question
A realistic time frame
A well-conducted, rigorous systematic review takes as much time as any other well conducted study. A recent analysis of published reviews found that the mean amount of time between publication of the protocol and publication of the finished review was 67.3 weeks, and that funded reviews (which are presumably conducted to a higher standard) took longer than unfunded ones.
Like any well-designed research study, a systematic review should include a protocol that describes in detail the objectives and methods of the review. If you're working on a Cochrane Review, you can search the Cochrane Database for examples of protocols. Another resource for protocol examples is the protocol registry PROSPERO. Developing and registering a protocol will also let others know that a systematic review on this topic is underway.
A systematic search
What is searched depends on the topic of the review but should include searches in several literature databases, as well as an attempt to identify relevant unpublished studies and grey literature.
A literature management system
You will need a literature/citation management system like EndNote or Mendeley to handle the large number of references turned up by your search. EndNote can be purchased through the U of C bookstore.