There is a great deal of information and resources on suicide prevention and related topics at the UCLA Center for School Mental Health: http://smhp.psych.ucla.edu/
A great website for 'projects implemented in schools, including teacher training, that promote mental health' from Australia is:
https://www.kidsmatter.edu.au/
"KidsMatter Primary is a mental health and wellbeing framework for primary schools and is proven to make a positive difference to the lives of Australian children.
KidsMatter Primary provides the proven methods, tools and support to help schools work with parents and carers, health services and the wider community, to nurture happy, balanced kids."