The pulse is the thing!
What one thing makes a good player different from a bad or mediocre player?
You might think that its playing the right notes (though not necessarily in the right order! (UK readers))
There is some truth in that, but its playing with a pulse thats is so important.
What does pulse mean?
I guess its the beat of the music - but beat has come to mean so many other things- the pulse actually drives the player to play, if you like, in time to the beat.
This pulse is so important in (most) classical music, but its VITAL in jazz!
How to check whether you're playing to a pulse, well one simple way is to play a familiar piece, one that you know well, and record it at the same time.
Listen back to the recording, maybe with a metronome, and see if all the notes are played to a pulse, you will soon see, if you listen carefully, if the piece you played had a pulse!
Come on a jazz workshop and you will soon see how the pulse works in jazz!