Looks pretty good for a modern city. My world is dystopian so being messy only helps, yours looks more like reality if that's what you are going for. Still, most cities get dirty, once you have the rest of those squares filled you should scatter some garbage/trash cans around. Get some fog going (or atleast a little screen tint) and some weather and walk around the map looking for anywhere that looks "empty," then fill that spot with something, even if it's just a chunk of concrete on the ground. Also try to keep track of how far apart the debris is. You don't want two of the exact same types of garbage right beside each other
You can also try editing that white ground tile to have a few variations (maybe darker if it's under a fence?). So that you can add dark spots around the edges or around buildings etc. Try and get rid of any areas where there are too many white tiles bunched together. Too much of the same ground tile in one area is never good imo
here's a quick image showing what I mean, the blue side has a different ground texture below the building making it look more seamless:
