well done with this zenithal effect.
check this article for some extra info:
https://paintingmum.blogspot.com/2011/01 ... ffect.html
and I would take a look at this article too:
https://chestofcolors.com/painting-faces/
see how to add some additional color nuances in shadows and highlights to make your minis more interesting and surfaces less monotoneous
it's great to see you got contrast so strong - this makes the miniature eyecatching and a great centerpiece (which it is supposed to be).
generally remember about the way most people look at miniatures:
1. first they take a look at the model in general, overall look. if the model looks visually appealing, interesting - they pay more attention to it
2. then they look at details and technique
contrast, colors, large elements or huge freehands are important at stage 1.
they're supposed to catch attention, to get the viewer interested.
at stage 2 you need details and technical skills - smoothness, interesting nuances, freehands, textures.
you did good work at step 1, now move on to 2.