What do you need before you get started on your review?
Do you have appropriate expertise in all the required domains for completing a rigorous review? Ideally, your team should include subject specialists, a systematic review methods expert, a librarian or information specialist with training in systematic review methods, and a quantitative methods/meta-analysis specialist (IOM 2011).
This is not an endeavor for the faint of heart. Depending on the subject matter, experience of the review team, commitments to other projects, and other factors, systematic reviews can take a year or more from start to finish. When assembling a team, you should always take these considerations into account and plan your milestones accordingly.
Remember that your systematic review should attempt to identify all of the existing evidence addressing your topic. To cast as broad a net as possible and minimize risk of bias, you will need to search for studies in multiple bibliographic databases, clinical trials registers, and other sources as appropriate.
IOM (Institute of Medicine). (2011). Finding What Works in Health Care: Standards for Systematic Reviews. Retrieved from:https://www.ncbi.nlm.nih.gov/books/NBK209518/
Lefebvre C, Manheimer E, Glanville J. Chapter 6: Searching for studies. In: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from http://handbook.cochrane.org/.