It’s always great seeing useless comments in place of actual helpful criticism.
Right now, OP, you need to try and work at not having everything look like it’s all just one big box. Texture placement needs to be worked on too, as many textures used don’t really fit the spot where they’re placed, or aren’t used in the right ways. The best advice i can offer to get better at doing that, therefor creating more “real” environments, is to do two things.
#1: Make sure everything’s set to a theme. Keep a type of style for the map and stick with it. Right now there isn’t so much a theme as there is just blocks with misplaced textures, but that’ll improve over time. Detail is everything in a map, so you need to use relevant props, decals, and textures to bring everything together into a nice, detail environment.
#2: Look for reference pictures online. Think about how you want to make something and what it’s supposed to be. It’s always helpful to be looking at things to inspire you to create something how you want it to be.
Another helpful tip would be to look into what a lot of standard dimensions for things in source are. Walls should, by default, be a certain height (depends on the environment but the standard for a plain building is 128 per floor). Things like roads also have certain dimensions of width (though i don’t think you’re terribly off from that standard looking at your screenshot, but i dunno). There’s a bunch of dev textures that help in doing some of that, like with brush based doors, walls, crates, counters, and other stuff. Take a look at some of them to work towards making everything scale properly for a player.
Mapping takes time to improve on, so you can only do better by continuing to work. What you have right now isn’t bad, but it needs improvement, and if you just keep working at it, you’ll start making things that end up being really really cool.
(also, in that last interior shot, you don’t need nearly as many lights for the place to be properly lit)