Nice paintwork, Josh! My compliments!
You have a steady hand, it’s all neat paintwork. I have a little suggestion but keep in mind that it comes from someone who hasn’t painted a single miniature in his whole life
(yet). I do agree with Corsair and Joansean about the use of black paint. Personally, I love the use of black washes on these models. If you pay attention to it I think it would surprise you how much black there actually is in daily life: in the clothes of people, in nature, in buildings. Most of it comes from shadows and dirt. Because the relief of the GW miniatures is – necessarily – too shallow, the black won’t show naturally. That’s why I would probably use a lot of black (streaks, washes, tiny dirt spots). What’s more, I think I would choose just a single ‘main’ colour, let’s say red, for the jacket of a miniature – or a series of miniatures, Dwarves or Elves. I would then try to keep all other colours on the miniature fairly nondescript: a flash of brown on the buckle, a hint of green for the trousers. Next I would wash everything with brown and black in a way that your first and only thought on seeing the model would be: “oh, he wears a red coat” - i.e. where colours are concerned. If I want to have gold on the helmet, again: just a hint of it – and a dirty one. In other words: I would paint my miniatures in black & sepia, with only hints of colours and nowhere exuberance. I think this will add to the realism but of course I would have to try first to find out for sure. Of course, mail shirts are an exception to the rule: mine would very much look like yours – that is: if I had your painting skills.
Again, these are the ideas of a non-painter.
I hope I can add something more serious when you start building your terrain!