As an orchestral clarinetist, I don't play concertos very often. I do it more often than others in my orchestra, but it's by choice. There is no obligation to do so. My job is as a principal orchestral player, which has its own set of challenges specific to the job. I could be content to play from within the orchestra, but I like to be out front once in awhile.
On the other hand, there are many clarinetists who solo exclusively, such as Richard Stoltzman. Once, while having a drink with him after he played a concerto with us a few years back, he said something like this to me, "I wish I had the skill to play in an orchestra like you. I became a soloist because I didn't get a symphony gig". Mind you, this was meant as a light and supportive comment to me. He is made to be a soloist, and I am quite sure he is every bit as much or more skilled as I to play in an orchestra. The point is, it's a specialization, like being a medical researcher versus being a doctor. Both are skilled in medicine, but one is more public.
Playing a concerto is a very different experience from playing in the orchestra. Not better or worse, just different. The feeling is more exhilarating, but also more stressful. The playing position is usually standing, not sitting, which changes the way the instrument feels as I play. Even the approach to sound is different, more open and "soloistic". By contrast, as a principal clarinetist, where I also get to "solo" from within the orchestra, the feeling is usually more reserved so as to blend better. Think of two paintings, one of a really cool looking cat, the other has a cool cat somewhere in the painting with people and furniture and books around it. I'm still the cool cat in each, but less prominent in one.
The pressure of concerto-ing is higher, much higher. After all you are standing out there right in front with everyone staring at you, rather than sitting, somewhat hidden about halfway back in the orchestra. Preparing a concerto is also far more time consuming than orchestral music. In my case, this is partly because I am much more familiar with orchestral music than concertos, since it's my regular job. So the preparation is intense and long. It usually starts many months in advance. I pick apart the piece and focus on the really difficult passages, breaking them into manageable mini-projects which I slowly build back together.
To hone my musical ideas, I listen to several recordings of reputable soloists, taking style from those players and forming my own interpretation from them. While learning the piece, I allow my imagination to run free with the interpretation, taking far more liberty in my phrasing that I would in the final performance. This is to encourage my muse to be creative. I find this is necessary to help break free of the habitual constraints of playing orchestral repertoire. In that case, I am interpreting only a small part under the larger interpretation of a conductor's.
Sometimes I hire a pianist to rehearse with, to get a feel for interacting with the accompaniment.
Yet, as a concerto soloist, one has more liberty to create a style which matches one's ability. Many factors are the choice of the soloist. Obviously the selection of a particular concerto is one. Otherwise there is the choice of tempos, the amount of rhythmic freedom, the amount of dynamic contrast, etc. Naturally, a soloist should emphasize his or her best features. If he is a more expressive player, the tempo can be set accordingly. If pyrotechnics is her specialty, then the style is set accordingly. Here again, as an orchestral player, I need to adjust my attitude toward having more control over the interpretation. But the resulting freedom can be very gratifying.
As the final days before the first rehearsal approach, I meditate on the music I will play. I hear it in my head, sometimes to the point of madness. Little snippets will run in a playback loop, over and over and over. But, thinking about the piece, getting one's mind around it, is as important as actual practice. When I play, I will go over the most tricky spots, playing slowly, cultivating a calm physical and mental attitude. I often say to myself, like a mantra, "You know this piece, you can play it, your fingers can play it. Trust yourself". It's so easy to become frantic as the day approaches.
I had one stressful incident in my preparation for a concerto recently. I had stayed up quite late working on reeds. (another post altogether) I placed the reeds on my practice table, cleaned the cat litter box, put out the trash for morning pickup, and went to bed. I acknowledged that I should have started working on those reeds a few days earlier to have them stabilize by the performance. (reeds, made plant cane, need several days to adjust to being wet and played) The next morning, the reeds were missing, gone. I looked all over the house, near the cat box, in the bathroom, in the trash, outside. I don't have a dog, so I only had myself to blame.:) In my fatigue, I must have inadvertently thrown them out with the cat litter and trash, which was then picked up the next morning.
Now I was really behind. I had to spend several more hours that day getting enough reeds going to give me a decent choice before the performance. A delicately timed schedule is easily upset.
Getting the right reed is crucial. Ideally, I can get on stage just before the first rehearsal to test my reeds and pick the one which flourishes in the hall. Our hall needs a full, resonant sound. It's difficult to pick a reed for that in my small living room where I practice.
After the first rehearsal of the piece, I can usually begin to enjoy the whole event. I say begin to enjoy. It's not over yet. However, many of the unknowns are now known. I know how the piece feels live, I know how my reeds are doing, or not doing, I know how the conductor will follow me, I know how I'll interpret the piece. I also know there's not a whole lot more preparation I can do. Back to the little mantra above, "Trust Yourself."
Now, my focus is to stay primed and calm, ready and poised. I care for my body and smile a lot at my Muse, for that's who will transform me from a person playing a concerto into a musician playing music. It's a world of difference.