Looked kind of like this at the first finish

I just went over it again with the steel wool and tri flow, looks like this now

And from the side it is practically a mirror

Is there any way to keep it this shiny? I've done this before to random things and it gets all smudgy and dark, like so

(looks like that or even worse)
Before I touched it up most recently it was beginning to look like that.
So, what can I do to preserve the finish? Hopefully something that doesn't require expensive or dangerous chemicals and really long and difficult treatments.
**edit: Maybe its just my laptop, but you might have to scroll to the right to see the slide on the right side of the third picture. Sorry