Make Sure Repeated Pitches Line Up
I can distinctly remember having a lesson with Joe Alessi when I was a student at Curtis where he tortured me over the first two low B flats that occur in the popular excerpt from Saint-Saens' Organ Symphony. It was really frustrating to picked on in such a way, but he was right!! If you want to make it very obvious to an audition committee that you have difficulty playing in tune, play that low Bb, then Db, and then come back to a low Bb that's in a slightly different trigger third position than the first one. A few mistakes like that are often followed by dismissal from a major orchestra audition. It's a difficult thing to get perfect, but it can be accomplished with diligent practice.
I would work to improve pitch, especially with repeated tones, by using a drone. The first line plus one bar of the Grondahl Concert, first movement, is a great example. Set your drone to a concert F. Play that first line plus one bar slowly, making sure that every F lands in exactly the same place. For the brief moment in time that you are playing the F, the sound of the drone should almost disappear to you if you're absolutely in tune. Once you get that right, repeat the same line and set your drone to an Ab. If you don't have a machine or recording that will drone for you, make a recording of yourself playing these notes as long tones. This can be quite revealing too. How steady can you hold your pitch? How easy are you to play with?