what the best way to level in hard core on d3?

i dont want to go past torment, idont want to die
i going for the achievement

from my experience on PC just starting it out you should probably just feel it out by increasing the difficulty until you can barely 1 shot or 2-3 shot most mobs.

Hell Rift.
Bounty in Act 5.
Just do it on a difficulty you feel comfortable.

There's a couple of guys who will help you through it...for some of that fg you don't use anymore