I played this recently, so spent a lot of time on it. It is difficult to sound good on this! Someone gave me suggestions: "a pleasing variety--contrast, elegant, charming, diverting, sophisticated," if any of those help. I also was overaccenting, so I have two things to say about that.
1. In general, when I'm overaccenting, I start practicing with obvious frequent accents and then gradually stretch them apart. I take a few lines and accent every "large" beat (every half note in 4/4 or the dotted quarters in 6/8 etc). It's pretty crude playing! but I only do it for 15 seconds. Then play again, this time accenting only the downbeats, so now I'm practicing using forward momentum where I used to accent. Then accent every other downbeat. Then only accent the natural landing place in the phrase, probably the second-to-last large beat. Doing this once in a while really shapes up my ear, which I think is often the thing to solve more than the hands.
2. Specifically in this piece, my first "fix" was to do the opening landing spots in tiers. In the opening motif, there's an implied "down" after each trill, plus the next downbeat is strong. I had to start with that last downbeat (F#) and decide how full I wanted that (I decided on pretty full, but not a big arrival yet), then back up one and make that a little less, and the note after the 1st trill a little less still. So I had very specific sounds I was trying to make at each of those points. Also in this piece, there's a lot of "short phrase-short phrase-LONG...." that uses the same material three times, the last time having a long extension. So wherever you would accent within the short phrases, don't accent that same note in the long version because then the extensions won't make sense to the listener. They won't catch the overall shape; it'll sound like three arrivals in a row plus some extra stuff tacked on, instead of two arrivals, then... wait... wait.. pushing ahead... there! arrival. If that makes sense. Also, if you're trying to make a different sound, try a different pedalling. Not just for the sake of the pedalling, although that will certainly change the sound, but also because a more refined and frequent pedalling can signal the rest of the body to approach the instrument in a more refined character without you even trying.
Something else that helps me when I'm stuck in making a sound is to re-describe it to myself. For example, to me "mf-pp-fp" notation isn't specific enough. If I were still playing the ms. 4 downbeat too loudly, I wouldn't write mf or whatever was less than what I'm doing. I would write "warm," or something else that described character or feeling. When I see the word warm, I definitely don't have the urge to bang, I just want to bring it out a little. The more specific I am about the sounds I'm trying to make, the easier they are to make. I guess that's my overall response to your situation: instead of telling yourself what you shouldn't be doing, imagine exactly how it want it be, with very specific sounds and shapes.
If there are particular places that are bothering you, I'd be interested to hear. I love this piece!
Best of luck.