This looks like the violin was poorly lit by an ordinary light source rather than by any "light painting". Sorry.
Can you elaborate please? Too harsh or flat? I think I need to be getting closer to the objects with the flash light. Different camera settings maybe or just better manipulation of the light? Would a non reflective object be better for a beginner?
The light is too "even". It's as if you're trying to get the light even overall. If you're going to go to the trouble of light painting, it usually turns out more varied and artistic. Camera settings are nearly irrelevant, providing there is enough time to do the light painting. I doubt if the reflectivity has any relevance.