Is improvise and improve not the same?!
Sometimes people mistake these two verbs to mean the same thing.
Improvise means to do things on the spot. It's spontaneous and instantaneous. Let's say you want to do a presentation, but because you have little preparation time, you've decided to go on with the presentation anyway. You know, make things up along the way and go with the flow. That is to improvise.
Improve, on the other hand, is to make things better than what it was. Let's say you've just finished that "improvised" presentation, and oh, no! It was awful. So, now you want to do it again, but this time, with proper planning. You want to make the content and delivery better this time. That is to improve.
See the difference?
Improvise: to make things up along the way.
Improve: to make things better.
Hope that helps!