Facing your fears and all that i'm going on the logic that if i practice in this environment enough I will get better of it. Plus I think it's a new level of learning a piece. Anybody can learn it "ok" but to practice it with the immense pressure of having to get it right every single time can really boost your performance in my opinion. Another thing I try to do, when performing pieces I think I have done is maintain conversations with people, chat about the weather the day etc while still playing. If i can perform without mistakes a piece that I don't have to put my 100% active concentration too, I know i've really learnt it.
I have read the music one ages ago and i recall it seeming a bit too good to be true. The author makes some pretty amazing claims on how his methods have assisted tennis players, musicians and even skiers if i remember.If i can find the damned thing, you are more than welcome to it as it is of no value to me.
How tight is shoe-string what's your location? We have Amazon in the UK you can buy the inner game of music for about £3. Possibly you can digitally download it somewhere where you live. I am massively nervous when performing, I don't think it's having people watching me or how difficult the piece is, simply the pressure of ensuring every single note is correct makes it very difficult.
I have both, and they've been helpful in my job, which is not music. They are both good, but, regarding the nerves problem, have you thought about meditation? Unless of course you're already doing it. Also: have you thought about the root of your issue? What causes the anxiety? Analyze it and maybe it will be a good thing.Oh and the most helpful person I've ever encountered with regard to these problems is the late American renowned psychologist, Albert Ellis. He wrote lots of books,and some of his hilarious lectures are available on YouTube. If I had to pick one of his works, it would be the book entitled How to Refuse to Make Yourself Miserable About Anything Yes, Anything!
I read both (although I couldn't finish the music one) and to me Inner game of tennis was superior to Inner game of Music. I think you can apply its teachings to many activities, including music making.