What is the quickest way to start improvising: play a scale over a backing loop and start playing with it. The course Playing With Loops is based on the concept of learning to play jazz by exercising over loops. Loops, chords, notation, example solos and extensive videos with explanations are provided to get you playing and improvising over loops.
If you don't have a looper, you can use some other recording tool or software, or simply use the pre-recorded backing loops in this course.
This will get you to practice more, and learn faster.