Helen your suggestion is very helpful. I think the centering you are talking about can also be referred to as grounding.
Sometimes I visualize myself being rooted into the earth. This helps me to feel centered and clear and as WyoWoman so beautifully expressed, allows one to be an empty vessel receiving the pure music from above.

Thanks Helen, this is an important point.
To be an empty vessel you need to calm the nerves. To calm the nerves it helps to center yourself.

Banjo Bonnie