improve (up)on (something)
To make something better or more outstanding. Your grade is pretty good so far, but I think you can improve upon it as the semester goes on. Do you have any ideas for how we can improve on this ad campaign?
improve (up)on something
to make something better. (Upon is formal and less commonly used than on.) Do you really think you can improve upon this song? No one can improve on my favorite melody.
improve on
Make beneficial additions or changes to, as in The company is trying to improve on the previous model. [Late 1600s]
improve on
or improve uponv. To make beneficial additions or changes to something; make something better: We can improve on this room by painting it. I improved upon the recipe by adding more spices.