By success I mean at least selling what the N64 accomplished WW or more obviously.

What can they do to make it happen?

Hardwarewise, it would depend on what the NX actually is.

Softwarewise, make as much heavy hitters as possible and avoid droughts during the first year. I think they are doing that already, they seem to be moving suppor from WiiU and 3DS to the next systems.

Nintendo lost so much credibility, that they're gonna have to pull off some miracles, honestly.

LOL xD

Balance their resources to have heavy hitters landfairly regularly AND without having titles of similar appeal clumped together. Market for a change. Haven't seen outright good marketing from Nintendo in seven years. And make nice with the third parties. Nintendo can't get success alone anymore; third party is just too big a deal these days.

More 3rd-party support and I'm not talking about the cartoony games. Only option is just to pay them to handle a good port with NX exclusive content. And of course the Mario, Zelda and Metroid and new IP's and everything else like magic...but since they are very ignorance and arrogant and blind.....

By doing a reverse Wii U. Making a real gaming platform that isn't weak, they actually market it. talk to 3rd party. If they don't do that, then they are dead in the water.

It will be whether or not it can have some kind of innovation that is both cheap and extremely popular (aka, NOT VR which is super expensive and extremely niche).

They thought tablet controller would be the next wii mote, but they didn't realize competing tablet companies would push them so far before the Wii U even came out. I suspect what they do next will be something that no one is even thinking about right now and they will try to capitalize on that.

Some ideas:

Complete voice command console where all apps, programs, browsers can be fully controlled by the voice. Also, they build games specifically with this function (RPG where you can speak one of the options out loud when given text choices, for example). It's designed so you can, if you want, not move a single arm or push any buttons but do everything by voice if that is your desire (but they shouldn't make it forced).

Go for extreme portability and have the "console" the size of a chromecast stick that goes directly into an hdmi port on the tv. Obviously the controller is separate and the device itself would be very weak in power (but think about how appealing it would be to take your console and go anywhere and plug it in and play just by unplugging it from the hdmi port.

I dont think NX (assuming its a home console) will be a big success. A moderate success maybe. The reason Wii U lost this gen will be the reason NX will loose. Its PS4. Bigger install base, bigger favor among third party, more power and cheaper. If NX wants to compete with PS4 / Xbox One then it has a gigantic mountain to climb.