I see you practice quiet well on composition, and boy that's pretty good. What I notice in almost all your art have one common thing. It's your further object are more complicate / detail than nearest object.
As nearer the object the detailed the object, so instead draw more detailed thing to your nearest camera.
I link a guy youtube video link below which has pretty cool architecture sketches, skip to 14:10.
Further Marc environment art practice video can be found in Term 8 & 9.
Once you comfortable, try paint it. Goodluck and Merry Christmas.