It depends on whether the person wants to be helped or not. If they don't, then I don't think there's any point in trying to convince them, since they don't even bother expecting anymore. If they do, then I'll try to make them think about what they love in life. Like, if they love cats, I'd ask them if they want to live longer to rescue stray cats and become a guardian to them. Another way I think could work is to make them see the solution in their own problems. For example, if they want to commit suicide out of the pain grieving over the death of someone they love, I'd ask them: "Would (the person) want you to live a happy life if they're still here?" (assuming that person is a good person). I won't be their hero or their problem solver, because at the end of the day people change for no one. They just change for the influence of someone. So it's best if you let them find their own solutions