Once you have developed your research question, you'll need to determine your inclusion/exclusion criteria - these are the characteristics which make a study eligible or ineligible to be included in your review. Here is an example of some of the common inclusion/exclusion criteria used in systematic reviews, which include:
In many cases, you can use the limits or advanced search features in many of the Library's databases to apply your inclusion/exclusion criteria , e.g., limiting your results by year of publication, language, etc.
It is recommended that a review protocol also be prepared, which is essentially a planning document that indicates how your review will be carried out. Here is a sample protocol template from the Evidence Synthesis Coordinator at the Maritimes SPOR SUPPORT Unit - this basic form includes all the relevant information needed for a simple protocol.