You're saying that it's impossible (or at least highly unlikely) for them to change to an N? Yeah, we know that. They know that. Everyone knows that. That's not what they're asking though. They're asking how to become more balanced, how to strengthen their intuitive functions, how to make some use of them, even if sensing will always overpower them.
Day dream!!! That is a start. I mean, how much easier can it be? The whole idea is to let your subconscious mind control the world and not your senses. True I may be pushing more a Ni theory here then Ne, but day dreaming is a N trait.
Not sure how this is hard to get across. My three beers tonight must be effecting my comprehension.
Studying things is a conscious state and will not develop your N vs S states. You will just come to a state of understandment that makes sense to your mind (S way or N way). You have to go subconscious to develop it.
Hell, if you must, start writing down all your dreams after work out, then imagine every possible thing it could be. Take a break, then write down everything it could NOT be. That second stage is making your mind think outside the box. Then after that write a story, in your mind, with both what you think it means and what it isn't. That will get your subconscious neurons firing to try and bridge meaning.
Still, I just say day dream, day dream, day dream to start. Then move to drawing but don't PLAN on drawing anything. Just draw. Keep drawing. If you think of ANYTHING that you want to draw...stop! Wait awhile then keep drawing. Let your subconscious draw it. That is N.
After you learn to let your subconscious talk, THEN you can start to apply it to conscious ideas (like mathematics) and you may see intuitive connections. But like every other "skill" in the world, you have to start very basic and perfect up or you won't mature correctly.