I think the best advice I can offer is that there doesn't really seem to be a set theme, the builds look good by themselves but they don't really work together.
You've got that very fantasy type house, but then you've got that one with the brick roof on the next hill which is more a contemporary style. They just don't work together, I'd recommend picking a style and building the rest of the buildings on the island in that style. It would look a lot more consistent that way.
Silveroug2 is right, the island doesn't seem to mesh together very well. Maybe work on that.
One suggestion I would like to offer is how the water is placed. See this image here:
You see how there's some waterbed before it flows down. I think it will look so much better around your lighthouse if it was like this. Or at least a pool of water with a river running off of it.
Also, I understand this is a work in progress, but the snow at the bottom looks really bad. It doesn't mesh with your island at all. I suggest making an floating island over a terrain that matches the biome you built on the island or over a void of nothingness.
Despite that, your islands looks interesting and has a serious amount of potential. I think you should keep working on it...just try to aim for a certain theme rather than plop down whatever.