I just made this, I’m not that good at building, but I think this turned out ok? can you leave some feedback and maybe some good plugins I can use for the future down below in the comments? thanks! 
Fixed ! 
I also added this ( just copied the model, and added some stuff) 
By looking at the image I can see some areas for improvements:
I’d try making the colors pop more the concrete material if I’m not mistaken could be something more appealing as well as making the door more detailed a sorting material or wood with the concrete could make it stand out more than the dull light brownish color used for the rest of the build. Try decreasing the amount of windows placed all around the build buildings in the real world normally feature two to three windows on the side and front.
You do want to have something that resemblance a corner build I feel like the material doesn’t match with the overall setting try finding a new one, while not overdoing it. That’s just a few things you could take. 
As for plugins I would try doing a quick search you could find tones of useful tools that’ll help you along the way: Search results for 'Building plugins' - Developer Forum | Roblox
I personally really like the design. The only thing I can see is if you where to put a little more detail into the door (handle, small rim, etc.) Other than that, good job! Looks nice!
On an architectural note, the windows seem pretty large for that size of building, as in if there were that many large windows the structure wouldn’t be that strong.
Also the 2 windows at the far left have a wider green pillar rather than the white vertical part the other windows have and the spacing of the windows on the top floor over the door seems a bit off.
Thanks for the feedback, I actually wanted to do the concrete like that because I am helping a military group im in build kind of a WWII era city. Thanks
Yeah, i see what you mean on the far left, That was a mistake I forgot to fix… Thanks for reminding me though!
Yeah, I will add that… Thanks for the feedback!