As a guest conductor, you walk into a situation you didn't create. First of all, you have to fit into an orchestra's programming schedule. The chief conductor has first choice of programs, then guest conductors suggest ideas for theirs. Either I'm asked “what would you like to conduct?” or I'm told “the program will be …” Normally, it's something between the two. A list of pieces I won't be allowed to do (because they're already programmed or have been done recently) helps me see the gaps and make suggestions. If the soloist is a celebrity, I may have to fit my program around his concerto. Settling a program can involve lengthy discussions among the conductor, his agent, and an orchestra's artistic administration.

The chemistry between conductor and orchestra is mysterious and beyond analysis; all conductors are more liked by some orchestras than by others. But we can naively attribute to “chemistry” a number of practical things. You have to assess the reality of the situation quickly. As you rehearse, you learn an orchestra's strengths, what can be achieved, what needs attention, what's best left alone. You learn how well (or badly) the players respond to your physical movements.