But the Charisma has to be manifest in every note and phrase we play, hence the Ability.
To the OP: needless to say, your question related specifically to a 'classical violinist soloist' but as per Buri's post I think you could learn a lot from looking at solo playing in other genres of music - be it jazz, easy-listening or street buskers. In each case you need to have something to say, or (since that is now a cliché) the music needs to be bursting out of you. If it is the technical challenges will melt.
https://www.youtube.com/watch?v=LaOSbBcPlfY
So, for what this is worth, I would say that my perception has always been that the players (whether great soloists and professionals or the rest of us) reach the heights when they are truly "in-the-moment" - technically, musically, and emotionally - and project that to the listeners. That's what makes it a truly blessed art form.
So (and here's the hard part)...How does one be fully in-the-moment?
Like Buri mentioned above, musicality must always be our goal.
I agree with David Burgess's comment too. I had the unsettling experience that I though my intonation was fantastic -- until I realized it wasn't. I was playing something for my teacher (I think it was my second lesson since returning) and my teacher stopped me and said, "That G is out of tune. It's too high." I said I thought it sounded right. So he proved it to me.
It took me a long time to realize that the teacher I had as a child, who was a wonderful violinist and who I greatly admired, was a total zero when it came to violin pedagogy. I didn't learn about "ring tones" until I returned to the violin as a middle-aged couch potato and got a teacher who actually knows how to teach violin.
One thing to remember is that -- for most people -- your ability to listen will develop roughly in parallel with your ability to play. So there's stuff you can't do now, and there's also flaws in your playing that you can't hear now. Another thing I couldn't hear as a teenager were all the scuffs and scratches while I changed strings during scale practice. It never occurred to me to listen for it.
I'd like also to mention something I saw in a video of Josef Gingold giving a violin lesson to Joshua Bell at an age when his full-sized violin looked too big for him, so he was maybe 11 or 12. Josh was playing a Dont study. Gingold told him that he should make his physical movements elegant, saying something like, "If it's not graceful and elegant, then it's wasted movement." I think it was about Bell's bow arm.
I really think there is only one way to achieve this:
You have to not give a #$%^ what anyone thinks or your looks, your style, your instrument - and of course most of all your playing. Hard? Not at all - I bet you are in-the-moment virtually every time you practice! If you can find a way to carry that into the performance hall all the fruits of the gods are yours.
An example:
https://www.violinwiki.org/wiki/36_Elementary_and_Progressive_Studies,_Op._20_(Kayser,_Heinrich_Ernst)
One can click on each etude for an analysis of fingerings as well as the youtube.
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It is important not to live in the past too much as well. WE rarely have an objective idea what happened then and its gone anyway. The only place to live is right in the present and that is actually rather hard to do but is the ultimate goal of playing the violin. Always think about the musical message you want to send, imagine the kind of sound that requires and experiment with the techniques that produce that elsusive but beautiful goal. You can only do this by what (maybe DeLay) said: hang your ears on the sound. Listen, listen to yourself.
Probably not too helpful but I did my best ;)
Buri