Kirk Whalum Blog
The key that unlocks the door of improvisational technique...scales. It's just that simple. If you are proficient at scales and scale exercises, you can be a very good improvisor. The only thing you'll need to add is a lot of imagination. God is already with you, so that part is covered.
So the main thing is to start where you are (the things you already know and are able to play) and move up a step each week. For instance, if you can play all your major scales at a decent tempo (I always recommend a metronome) then you should move on to playing them in 3rds: C-E-D-F-E-G-F-A-G-B-A-B... etc. LEARN THIS VERY EVENLY IN A SLOW TEMPO IN EVERY KEY BEFORE MOVING ON. THEN LEARN IT IN "REVERSE:" E-C-F-D-G-E-A-F-B-G... etc.
Do this in every key.
Then learn it in the "melodic minor ascending." Then do it in "harmonic minor."
Now there is lots lots more, but I guarantee that what I just described will take you at least 8 weeks.
The idea is that the more proficient you become at these basic, boring things, the more head-room you'll have to translate your creative ideas from your head and heart to your fingers. You must be both diligent and patient.