Here are some thoughts on improvisation...
there are basically two things you are practicing... The first is developing an awareness of your instrument. That means.. learning how to play chords (in the case of jazz, chords that include extended harmony ie.. major7th, 9th and so forth) all over the neck, and soloing over those chords. You can find all kinds of books, videos whatever on this stuff... There are as many approaches as there are teachers but if you keep looking, you'll find someone that fits your style. Here is some of my stuff... it may help or it may not...
Lessons | The Belltower
The second is developing YOUR musical voice which might mean you need to start listening to great improvisors... start with the ones that play your instrument and then branch out to the other well known players in the genre.
My last thought is to have fun! Playing music is an incredible thing. Best of luck.