1. The tiles used here clash very much. Try sticking to a single color or two for an exterior building. Using mostly grayscale tiles works wonders. Less is more!
2. The trimming needs some work, the cutoff is very apparent with the ground in this particular instance.
3. Again, less is more. I was very confused with the placement of these tiles.
4. As previously stated, the perspective leaves a lot to be desired in some places. This also applies with the extremely tall walls of the main building. To remedy this try to make multiple floors of 5-6 tile high walls
5. There was attempt (?) to detail the grass but this is obviously not enough! Try to vary the grass by adding gardens, paths, etc.
6. Take a look at existing beaches in Era for a better idea on how to transition grass/sand/water.
This is one of my biggest challenges with leveling as it takes a lot of time, but mastering realistic transition between these will reward you with a beautiful end product.
The indoors level is highly problematic, try to stay consistent with your theme, make sure there are walls of equal height in all areas! (Office has no walls!) and make sure to use NPCs, as I think a few spots need to be covered up.