Steps for success:
1) Completely fill up one or more smelter(s).
2) Go do literally anything other than stare at them. Hunt for meat, feathers, etc., grind sneak/swimming skill, tend the farm, start planning that expansion to the house, go fishing, cook some food, etc. Or, y'know, just go to bed.
3) ?????
4) Profit. (look at all those metal bars you just picked up off the ground)