I’m quite pleased with this exercise but I tried to achieve as much of “pro archviz” look I could get - but something still feels a bit off to me and not as “clean” and visually attractive as ie source image of the reference project I took from the house projects side:
I spent loooooooooog time playing with the lighting (ending up with just Nishita sky) and I know that the quality of the assets and materials themselves could be for sure better here and there (I haven’t used any paid addons for greenery, everything is done from scratch or with free tools + a few models from the web like flower and ball :P) but I welcome any hints what could be improved here (composition mainly perhaps?)
There is also almost no post-processing done, only some minor tweaks in Blender compositor.
Non archiviz user here : nice maybe it’s the grass which is to wild and realistic for archiviz (no accu mower) or more stone plates arround the house (no nature needed here )? And maybe the unsharpness/unfocus…? (again for archiviz) Just a thought.
lighting sure looks good! it’s definitely paid off. I do think the house should have some sort of texture on it, and the sky windows a little more detailed (but it probably doesn’t have to be way more detailed.) like I think the bevel is a bit too strong on them and it distracts me a bit. Maybe a bit of texture on the porch or at least turn up roughness cause i think it’s a bit shiny. Bevel the chimney and the gutter shape. But yeah I mean getting the lighting right is like more important in a way then modeling and it really shows. THis is great so far! Patio and nature are very good and convincing.
Oh the tall windows I would pull out a bit more too.
Actually I was going to comment that you could add some “dirt” to the house to make it more realistic as your image is quite close to realism. Then I saw you want the clean archviz look. Here are my observations:
remove the particle grass (as mentioned in previous comments it looks too wild) and only keep grass texture on ground
Round out the edges of the drainage pipe coming down from the roof (mentioned in previous comment about beveling)
Add some reflection to the windows. Notice the source image has trees reflected in the roof windows
Add a vignette in compositor (again based on the source image )
The lighting is too harsh. If there is a sun, tone it down and use more of hdri.
Agree with a previous comment about toning down the light/brightness, there’s something about the white in the house itself being too bright that makes it look cartoonish, adding some texture would also help. I think you’re done a great job!
: nice maybe it’s the grass which is to wild and realistic for archiviz (no accu mower) or more stone plates arround the house (no nature needed here 
)? And maybe the unsharpness/unfocus…? (again for archiviz) Just a thought.