First off, your map has no lighting. Stick a few lights in there so everything doesn't look so bland and eye-stabbingly bright.
Secondly, from the looks of things, your map is just a series of boxes, which is forgivable for your first ever map (which I presume this is) but is ultimately not terribly interesting. Try to vary things up with the layout - take a look at other maps and see what they do!
Also - the least of my concerns, I know - but Spytech equipment in a wooden environment doesn't make a whole lot of sense. And the resupply locker in screenshot 2 is floating.
Overall, while you've got the basics of the map right, you may want to scrap this map and start on a new one. If you're interested in making a Capture the Flag map, take some time to study existing CTF maps and see what makes them work.