Dean Giustini and Diane Helmer presented a workshop Finding the hard to finds: searching for grey literature at the 2006 CHLA/ABSC Conference in Vancouver, Canada. (Powerpoints and manual are available)

At the UBC Academic Search Google Scholar blog Giustini lists five top skills needed to find grey literature in health:
1. Expertise in conducting exhaustive literature reviews in health.
2. Knowledge of publish trends (traditional publishing vs. everything else)
3. Knowledge of sources of information beyond MEDLINE, EMBASE, CINAHL, etc.
4. Knowledge of major U.S. and Canadian agencies that produce grey literature.
5. Expertise in project management and librarian advocacy.