I think the point about analyzing the impact of your death on other people is extremely crucial.
Finding an external motivating force is essential to making it out of a depression situation. You need to draw your mind's attention away from yourself and your problems.
Social service is also something that works well - not only does it keep you busy, you often come into contact with people who have far more severe challenges in life than you. That's some valuable perspective when you're contemplating suicide.
