One of the best ways to learn how to improvise is to transcribe solos by your heroes.

I've been transcribing Django solos since I started to learn this style. It's the next best thing to having Django show you how to do it, as he is in the photo opposite to his son Babik.

I don't generally write out transcriptions but I do have a couple on the lessons page: My Melancholy Baby , It Had To Be You and Improvisation #4