Once the question is developed, do some initial searches to ensure that it is manageable.
Too much
If searches give tens of thousands of results the topic may be too large to manage.
Try to revise the topic to make it more narrow. This may include focusing on one aspect or adding more criteria.
Too little
If there are less than a couple of hundred of results then the topic may be too narrow and there may not be enough results to review once inclusion and exclusion criteria are applied.
Try to revise the topic to make it wider. This may include removing some criteria.
Use the Search section of this guide to help devise search strategies and determine where to look for information.