I did a visualisation for a project I am working on in the architecture office where I am working. Rendered with cycles 500 samples on CPU i7 6900K @ 4,1Ghz because it was faster than my two GTX 1070. Comments and critics are welcome.
One thing that is really obvious is the bad grey wall texture… you should change it and find a bigger one that won’t be this repetitive.
Well since critics are welcome… 
The grey wall texture is indeed very bad the grass is also quite weak. Give everything some variety, at least some flower or a yellowish grass here and there.
And in the completely empty (no lights, no stairs, no furniture, no life) environment the two lone chairs randomly placed and drowning in the tall grass are (to be honest) laughable.
And the flat gloomy lighting gives it almost a post-apocaliptic feel.
And right away I apologize, sometimes I come off very harsh and it is obvious that some work and skill was put into this. But if you want my honest opinion. Work on it a bit more. Give the picture some life and more of a happy feel I guess. (unless the purpose of the picture is somthing else than making it look appealing)
I completely agree with .Adam. I am a landscape architect, not an architect, so I have no right to critique the building design (minus the bad textures used). That being said, the landscape is pitiful (typical architect mentality 
) Composition-wise, you have a background and middle ground, but lack a foreground and that gives the image a lack of depth. The feeling of the scene is dreary, and is a place I would not want to visit…feels like prison housing. The client will want this place to feel alive with activity, if you are selling a design idea. Add some outdoor amenities (i.e. patio, fire pit, garden, paths, etc.) and put some people in the scene. Brighten the image and use a less cloudy sky. The image has potential, just spend a few more hours finishing it. Also I just realized the building is completely empty - I would add some components inside and on the decks to bring life to the building itself too.
Thanks for the constructive critics. I have to say the time I spent to make the design was much longer than the time I worked on the visualisation, because I did this in my free time and not at work. Now the client wants an other design and it beginns new. Maybe my boss let me spend some time at work for the visualisation next time. I have say that nobody at my office has experience with visualisation, and for this reason I am realy happy about the critics.
They walls was the first thing that I noticed as well.