I think you have to wait until you are truly ready. I have had moment where I think I could have gone through with it, these moments always bring me peace.
Unfortunately, I don't know how to summon these moments. I got some very bad news yesterday (my economy will crash and burn at some point in the near future), would have thought that would bring "The moment" back, but it didn't. Expecting that it will return when shit actually starts hitting the fan, and then I will be ready to act.