"Sometimes you need to stand with your nose to the window and have a good look at jazz. And I've done that on many occasions"

This quote by J. J. Johnson is a metaphor for making the effort to actually value and comprehend jazz music. He is recommending that one need to take the time to really listen to and research study jazz music, as if they were browsing a window. By standing with their nose to the window, they can take in all the details and nuances of the music. Johnson himself has done this sometimes, and encourages others to do the same in order to truly value the intricacy and appeal of jazz. It is a tip to take the time to really listen and value the music, and to not simply pass it by without offering it the attention it deserves.