Oh sorry I wasnt able to reply very soon. Whatever style.
I think you can take ideas from jazz and apply them to classical. Take a melody and chord progression and voice it out yourself. Take the chord progression alone and create your own melody.It's about being flexible with the rules. Some things reamin fixed. Some are up to the performer.It's more like a language. Lots of "vocabulary" learning can go into it. I never really thought about it much, but then someone explained how much improv can also be "planned." More like speaking when you know what point you want to convey, but don't know exactly how you will say it and you have a full command of words and phrases at your disposal -- which turns out good sometimes and bad others. The classical "prepared" way would be like reciting a speech in that analogy.