You must have a natural authority; disobedience shouldn't even be an issue - you make the orchestra do what you want by force of your musical personality.
Don't talk too much in rehearsal. Players don't want long lectures about the history of the piece; they want crisp, precise instruction. They get bored very quickly.
You must know how to play at least one instrument - understand how the instruments work, know what each one is capable of and what you can demand of them.
Conducting has one major disadvantage - it is something you cannot easily practise; but you must find a way. Start your own amateur or chamber orchestra and conduct it - that's what I did. Reading about it will not give you any idea of what it is like. A performance is the moment of truth; you can't hide behind anybody and you can't chicken out. You must be sure of your vision of the piece, and communicate this using your body, your arms, your eyes; the tiniest gestures mean a great deal.
The majority use a baton, but others prefer to use their hands. Some conductors achieve what they want very quietly, whereas others throw themselves around. I don't know where I fall; I'll let the public judge.
Jan Latham-Koenig will conduct the Opera du Rhin production of Poulenc's `Dialogues of the Carmelites' on 4 August as part of BBC Proms 99. Box office: 0171-589 8212