1. Realize that you have put a machine on the market with a heavily limited appeal, that has close to zero chances of ever reaching the hights of its predecessor
2. There are two possible scenarios now, one that should happen if Nintendo really wants to change the course of the Wii U (a) and the one Nintendo will probably approach.(b)
a) Fire Iwata, rearrange the management and think of something new, something mindblowingly amazing that nobody here could expect, that's something people don't seem to be able to grasp, what the Wii U needs isn't a new Zelda or Smash or MK, or a new bundle, or even a pricecut (unless it's a really significant one), it needs something completely fresh and new that none of us would think of, a completely new direction.
b) Make the console cheaper to make and only cut the price once you can still make money even after the pricecut.
Now continuing after (b)
3. Make your standard games and make money with them. Basically make sure you get money out of the Wii U.
4. Start thinking about your next console (or if you want to make one) and think real hard, cause by now you should have realised that Mario alone is not an easy recipe for success anymore, so you'll need a better product next time.