Don't quote me on this but I don't think the hammer method would work too well. I doubt the angle that you would use in order to strike yourself would generate enough force to kill you in one shot. I imagine that it would be very likely that you would strike the hammer once, which wouldn't be enough to kill you but would be enough to incapacitate you to the point where you wouldn't be able to go for another strike, and may leave you with brain damage.
I also don't think exposure to the elements is the best way to go. You will most likely either die by starvation, heat related complications, or hypothermia, which are all very terrible ways to go. The only other way you could die from exposure to the elements would be a lightning strike, which even when all the conditions are perfect would be highly unlikely to happen, and even if it did the survival rates are too high.