The level has a good variety of dust textures used to make each building a different style so very well done there. Use of props, displacements and proper lighting also.
Some things to consider on your next map,
Basic optimization, even for a map of this size is still important, you have a lot of faces on the outside of the level or unreachable areas still textured, see below. Use the Nodraw texture on these faces so that they are not rendered in-game. That will help to improve framerates dramatically.
Small note, your tables in the market place are floating ever so slighting.
Texture application is good here, you just need to do a bit more detail brushwork however, the interiors are rather plain looking as one solid texture, either choose another or split it up into a few different textures. Your floors also don't line up, try fixing this or keeping it in mind for your next project.
You have some overlapping brushes as well, avoid this as much as you can, its a bad habit and makes for some issues with VVIS that can be avoided by proper construction.
While you have some nice inaccessible areas near the CT spawn closer to T there is a gap in the wall that allows you to see the skybox and ruins the effect of the environment as it appears one is simply floating in the level then rather than being in an actual location.
Try using a 3D skybox as well, and get away from using the default sky texture too. This site has a large collection of custom ones and Valve still has many other built in ones that are nice looking.
The level has no soundscape so all one can hear is their own footsteps and gunfire. Look into some basic soundscapes as well as a radar overview file.
The tutorial section is your greatest resource, check it out from time to time.