The first and most indispensible aspect of good jazz improvisiation is mastery of your instrument. This is vital because the essence of improvisation is the ability to gauge the mood and pace of the music as it develops, and to be able to react instinctively and simultaneously to add both to the atmosphere, and continue the development of the music being played. Equally important is the ability to listen to the other musicians involved, and be able to gauge when to take over and lead, when to follow and harmonise, and how to assess the mood that is being created by the musicians as a whole, and develop its themes and ideas. Ironically, although the essence of good improvisation is instinctive playing, it is possible to attend classes where the rudiments of improvisation are taught, giving the beginner a grounding in the basics, from which a more individual style can be developed.