Students on one of the London Organ Improvisation Courses Improvisation at the keyboard doesn't come naturally to every organist, particularly if they were drilled old-school in their youth, with teachers highly disapproving of any attempt to make things up as you went along.  Watching YouTube videos of top improvisers in full flight is all well and good, but isn't necessarily going to bridge the gap between skills.   Sitting down and doing it is the best way to learn - with sympathetic guidance and a graded approach. Two summer schools are coming up in July devoted simply…