That's pretty impressive, mking! Definitely keep it up!
Remember that one of the awesome advantages to digital work (I presume this is digital painting?) is that you can lay over corrections and sketch Layers to help yourself out when you run up against a difficult aspect. So for instance, when perspective is giving you a hassle, throw down a new Layer and put those VP guides on it, then turn off the guide Layers when you're done. Remember that your assistance Layers like VP guides and sketches are in no way restricted by the needs of final printing, so the lines can be in whatever color helps you best (I like blue and red myself).
And when you sketch, nobody needs to see it, so you can be as rough as you like. I often do what I call "scribbling with purpose", which is when I have an idea of what shape something should be, but rather than trying to get it right the first time I "zero in" by laying down as many line as it takes until I get the one that defines the contour I was looking for. That's the one I use when drawing the clean edge, but the others were just as important in finding it.
Other than that, my only crit would be that I imagine Luthadel with more towers and smokestacks (from the factories and canneries). I think of it as more Victorian than Medieval, but I don't have any particularly good excuse for that aside from the impression that stuck with me after I'd finished the novels.