I will start with the lightning, I would really recommend to configure the light_env and adding a env_sun to emulate a realistic environment, also adding "lamp" props and using light entities and sprite (to emulate light glow), also using shadow_control and the lightblock tooltexture to improve the shadowing greatly, like with the fruit crates, they really should have that tooltexture.
also about those fruit crates, the the playerclips should be altered, as of now they emulate the look of standing in mid air in some cases. use props such as windows on the buildings and walls to fix the plain and blocky look. Maybe make a some parts of the sorrounding walls destroyed at some places to improve the brushwork and give the walls some character, also some more static models as most models are physics, static models add great detail overall. some leaf decals under the trees. add some soundscapes, with bird sounds and more nature sounds, remember sounds can add a great deal to the level, some more cover would be nice, as IMO the cover that is currently in the map is not enough.
add some sort of flowerbeds for the flowers that are around the map, and fix the grass randomly coming up from the tiles, easily fixed with the blend tool. when standing on crates looking through the small windows you can see the skybox under the buildings, which is not really THAT noticeable but remember, it's all in the little details.
overall the map has great potential but the walls surrounding the map seems a bit to blocky, I liked that you used a blend material that has grass sprites defined in detail.vbsp . I would love it if you made an updated version of the map and sent me an PM with the link to the updated version.