All in all, for a first attempt, I think you have done really well here. I guess what suggestions you are looking for depend on whether this is intended to be more of a show piece or a solid tabletop paintjob.
Assuming you want to achieve more of a \"show\" quality, the things you could work on are:
1. Increasing the amount of colors (and therefore the amount of blending). This is always key when doing NMM. Right now you can detect too much of each color, especially for such large, flat areas.
2. I would also try to mute the colors a little bit; especially the blue.
3. Lastly, try and add reflective spots/highlights to the plates that create the illusion of reflection. Kinda hard to explain, but with SENMM you are trying to simulate how light plays off of a highly reflective surface. The reflection of the surrounding landscape (the blues and browns) is one part. The second part is a pure (white) light reflection that hits in different areas depending on the shape of the surface and light source. For example, on his shoulder a curved highlight on along the blue area would suggest a typical overhead light source. I\'m not sure this makes any sense, but it\'s tricky to explain
Your\'re just trying to make the space look like it\'s a very reflective surface, and not a surface that has a picture of a horizon painted on it.
Keep up the good work. Very ambitious to take on a model like that using SENMM. You have the right idea and you idea of where the horizon lines should go is pretty on.