The most important is
intent.

She writes “Without purity of heart and mind, true and lasting healing cannot occur. At the beginning of every healing process, whether or not it involves song and music, a short prayer or blessing should be uttered…. Before I sit down and write a composition for healing, I clear myself of all negative thoughts and say a short prayer stating my intentions. Even before choosing music for healing, a prayer helps me focus on the purpose for healing music”.
Joanne Dusatko- Compositi