Two blogs I enjoy reading are those of bassist Michael Hovnanian and baritone Kyle Ferrill. Both performers offer interesting technical comments on performing, whether it be bass fingerings in standard repertoire or larynx positioning and its impact on vocal timbre. I am neither a bassist nor a singer, but these insights are helpful to me as a composer. Every bit of information like this helps me ground my work in the physical realities of music making.
Hovnanian is also very funny regarding life as an orchestral musician. In a more serious vein, he offers in this post some interesting stats on the near impossibility of getting a second performance of your orchestral piece, and the disappearance of repertoire from the recent past.