- Is the conductor trained as a conductor from beginning or is it so that a really good player of some musical instrument may eventually become a conductor? Can actually a typical conductor play himself at least in free time?
- If the conductor is specially prepared, how it is possible to become in charge of all orchestra just after getting a master degree? Maybe some intermediate CV steps exist between graduating from and obtaining a conductor position?
I can't speak about CV advancement, but I would add the following to @Fabricio's list of what makes a good conductor:
- Knowledge of how all instruments work and are played, e.g. will two alto flutes playing in unison be heard above the viola section playing sul pont? Will it be different when the hall is full instead of empty?
- Experience with the mentality of different instrumental players, e.g. when to encourage vs. discourage the cello section (Joke: how do you get a cello section to play fff? A: mark it ppp espressivo)
- Like a dancer, a subtle command over every part of the body (once, I accidentally cued in a player at the wrong place just by looking at her to see if she was ready for the cue)
- Complete and lasting memorization of a great deal of repertoire, such that an endless string of moments which require special attention can all be anticipated and then executed perfectly
When a musician of any age shows this kind of mastery, s/he is ready for conducting. However, it is often impossible to convince anyone else of that unless s/he also shows immense skill in another musical area, such as performing or composing.
First what makes a good conductor. Being a good conductor requires three things:
- a broad knowledge of music in general and music theory in particular,
- the mastering of musicality and, last but not the least,
- very strong management and organisational skills.
I believe point 1 is obvious. A conductor must be able to look at the score and make it sound in his head to then be able to make the orchestra play it. And it's not just a monophonic instrument like a trumpet or a clarinet, or even a polyphonic instrument like the piano, it it's a concert score with all the voices being played in the orchestra.
Point 2, although obvious to many may not be so to others. The sense of musicality is the capacity to play or understand when a piece of music is well played and where instruments are played in harmony: properly tuned, in the same tempo, not overshadowing each other, using the same nuances when they are needed, etc, etc, etc... There is much more to it but I'm sure you get the point. If a conductor doesn't have this sense of musicality he will never be able to direct his orchestra and make it express itself at its best.
The last point is not obvious to most people. But look at it from this angle: the conductor must manage an orchestra of 50+ musicians where many of them may (or surely) have oversized egos and a strong opinion on how a certain piece should be played. So, you can imagine what it takes to manage such a large group of people.
Now answering you first question, how to become a conductor, although you can follow studies in the area, in many cases conductors are just musicians that started either assisting a main conductor or started conducting smaller ensembles first and grew up to orchestra level.
And of course nothing stops a conductor from being a musician him or herself. But growing from musician to conductor, as in any other profession may risk running into Peter's principle... ;-)