I stick to the written music as much as possible - crescendo/descresc, loud, soft, speed, etc. When it becomes "fuzzy" as most things are with me, I look at the composer, and when he wrote the thing - early Beethoven might be more "conservative" on the pedal, for instance, than later Beethoven for example. I do the best I can, then do what my teacher ultimately tells me, since knows more about this stuff than me.