As a parent you need to spend quality time with your child. Listen to him. Don't talk at him. Share your experiences and feelings. Be available. Keep firearms and other weapons locked up.
As a student you need to be aware of what is going on with your peers. If you notice somebody acting strangely or talking about 'ending it', take it seriously. Get help.
As an administrator you need to promote awareness of suicide. You need to proactively hold training for suicide prevention. Create 24/7 access to an anonymous suicide hotline. Offer help and counseling. Above all do not stigmatize students or staff for reporting information.
As a teacher you need to be accessible. Be attuned to the warning signs. Act on them.
Suicide is preventable. But the school community needs to help prevent it.