I've recently made these, but I don't want to call them finished just yet;
Some things are bothering me with both; but i can't quite point out what.
I hope you guys can help me improve these, as I'm not a very experienced person.
Thanks in Advance!
In the first one, all that empty space on the left is not needed. If that tower is the focus point of your painting, I'd advise to crop it or add something of interest in the empty section of the image. Assuming you're working in a 3D package, the lighting can be improved a great deal in both images. In the first one for example, the sun's light is yellow, therefore the shadows will be blue. There will be a secondary light source coming from the sky and reflections bouncing off the water. It took me longer than I care to admit to notice that little boat. It would be a lot better for the viewer if you place it on the other side so the light hits it or use composition to bring the viewer's eye to it.
The way the city disappears in the fog is unconvincing. It looks more like it simply vanishes into thin air rather than disappearing in the fog. Also the perspective is wrong on that one. If you take a line from the ship closer to us it disappears into the sky, rather than meeting the suggested horizon.
Hope this helps!
For both, try adding a 'frame' to the images by creating foreground elements on the edges of the pieces with nothing really there. So in the top on, on the far left of the image, try adding in another tree and some grass but not as much as on the right. For the city scape, add something darkened out that is standing close to the viewer. Give it ago in these and try it out in the future.