I found this map through the mapcore forum, and it caught my eye because of the underpass that leads to bombsite A and the warehouse outside of the site. I think that it has potential.


As a hammer editor a few hundred hours less new than you, I have several suggestions for you:


Nav mesh
It seems you are using an unedited nav mesh on this map, which you may already be planning to change. The ladders in the level are inaccessible to the bots using unedited nav meshes, and there are quite a lot of bad camping spots in it. Some of the stairs on the way to A are also unclipped on all of the steps or the bottom one, which has made the bots think that they should jump when they get to the bottom. This makes playing at bombsite A quite lonely when playing with bots because the terrorists are unlikely to use the underpass, and the CTs can't use the vent or balcony to get into the site, so they have to go all the way to the furthest entrance.

Models
The props with shells in them seem to be from de_mirage, and they have a fundamental problem of having hitboxes and models that do not line up properly (you can see through some of the gaps in the model, but you can't shoot through them). WarOwl (a guest expert in the contest) hated these props when Valve made their version of de_mirage, and he may be displeased to find them on your map as they are; de_mirage has since been updated so that the models can't be peeked through as well.

A lot of the models are a little tricky to walk on and around, so I think you should add clip brushes around some of them.

There are small cracks on either side of the doors, which you should replace with prop doors.


Layout
Middle is a little bit messy to me; I'd suggest either removing or extending the wall over the archway on the terrorist side over to the wall on the other side.

I don't like the ramp up to the balcony overlooking bombsite A; I think it is too thin and a little featureless; consider expanding it to be a small room or series of corridors.

It is usually not considered a good idea to have only one terrorist entrance to a bombsite; consider another way in through middle or 'apartments,' although it may not be much of a bad thing on this map.


Other:
I usually prefer not to use steps with a 1:1 45 degree angles in my maps; in-game, you seems to go up them too fast, and if there is a sloped wall above it, a player jumping through the corridor is likely to bounce off the ceiling.