Hi there! Hyrule Shield, always nice to see
You're on the right track, but I hope I can explain a few things:
1. Your gradients seem to be quite random, especially on the red shapes. I wouldn't expect the light to fall on those that way.
2. Try to use less fine lines for the highlights, they are distracting this way, and over used. I wouldn't expect them everywhere.
3. I think things will improve big time if you don't use those fine sketchy lines (black and white). Use fatter (vector) lines or paint over them.
Hope that helps