im not saying you have to go out an round off every square coner you got, but stuff like giving doors door frames and windows window frames and giving the stairs supports, and instead of the stairs being squares, have smaller rectangles or slope the bottom of the stairs.
and like in the second screenshot you could add a little lip around the top of the room, its small things like this that can make all the difference. also make sure that not everything is the same, ill just show you a quick example of what i mean from a map in progress from me
see how it could easily be one long straight wall in all the screens, instead i break it up by putting some variant in depth in, especially in the 2nd screenshot, beginner practice would be to just make it one long flat alley.
use techniques like that in your make and it will improve it heaps/