Grey literature is vast and not systematically organized so it helps to find ways to narrow down the scope of your search, for example:
Who are you producing the information for?
Knowing who you are creating the information for will help you determine which grey literature sources you want to include.
What kind of literature are you interested in?
What time period is relevant to your research?
The last 5 years?
UBC Grey Literature for Health Sciences: Thinking Through the Process
Nova Scotia Health Authority Library - Grey Literature
Essential Information to Include in Checklists/Tracking Sheets
Grey Literature Checklist & Tracking Template
http://library.nshealth.ca/GreyLit/Tips
Grey matters: a practical tool for searching health-related grey literature
Here are a few starting points for finding grey literature: