Ok First off: Lose that background, the diagonal stripes really detract from looking at the mini. I find it uncomfortable to look at due to my astigmatism, so others may be in the same boat.
As for the mini, overall the contrast range isn't as large as it needs to be. You don't have a definite Dark nor a clear Highlight. This is shown mostly on the grey of the armour.
Also on the face there is not enough tonal range for highlighting try adding a touch of Purple to your skin tone for the recesses in the cheek areas and perhaps a tiny glaze of dark red into the hair border.
If you are wanting to go and try NMM you need to remember that metal reflects light in specific ways. Try looking at Cutlery in differing lights to see how round and flat surfaces reflect the light and have "Flare spots" of
almost white.