Check out the Essential Tools and Resources section on this site.
In addition to the tools and resources you will find there, the following links will take you to more essential guides, tools, and other technical resources for prevention and response to gender-based violence in humanitarian settings:
IASC Guidelines for Gender-based Violence Interventions in Humanitarian Settings
Sexual and Gender-Based Violence against Refugees, Returnees and Internally Displaced Persons
IASC Gender Handbook in Humanitarian Action
Clinical Management of Rape Survivors (2005 version)
Population Reports: Ending Violence Against Women
WHO Ethical and Safety Recommendations for Interviewing Trafficked Women