here's a suggestion. Since you seem to have a good grasp on the technical aspects, perhaps the emotional side is lacking. Does the music that you are playing evoke an emotion in you? I know, touchy feely
, but is the music trying to portray pure unadulterated joy, or absolute anguish, or read-hot anger, or a rainy day pensiveness, love, wonder... Maybe if you really try to feel an emotion deeply while playing the piece it will come across better.