I can never figure out how to make a well made, cunstructive and decent buildings, if you post tips to help me that would help a lot thanks.
I would suggest looking and searching in the aesthetic maps. You can learn a lot from maps there..... Well, most of then anyway.
Depends on what you are going for. If you aesthetic purposes, look at some of the aesthetic house maps. If you are looking for gameplay, than "separate areas" are more important than straight up buildings. For me, I like using box floors, some box walls mixed with walls, and not necessarily a ceiling but, that would be walls. Make sure you have multiple ways in and out (2-3), and that the room is at least big enough to fit a standard king hill. If the room/area doesn't feel like somewhere a team would want to control, try putting a power weapon in there to increase traffic. Avoid a shotgun though, as you don't want people to hunker down and hardcore camp it. A sniper is a good idea, than the weapon has to be taken elsewhere to be used.