This is a lovely start. Here is what I would suggest that you experiment with. It should make the painting look better and should help you play around with your colours a bit more if you do it.
1. Wet each of the stone sides with pure water (one at a time). Once it is damp, stand the painting at a 45 degrees, and drop a small deop of grayed earth colour in the bottom right corner of the stone side. Let the colour do it's thing. If you are careful and don't add too much water to your colour drop, you should get a very nice and natural shadow.
Now let it dry, turn your painting upside down (still at the 45 degrees) wet the entire sky with pure water starting between the buildings and pulling down. Let the water soak a bit, then drop some concentrated cobalt blue or similar blue between the buildings and just above the roofs and let it spread to the rest of the sky. If you use your brush VERY lightly, you can guide it as well. leave it alone and let it dry.
Now take some very light veridian or some cold green almosta tint no colour almost and cover the steeple and the dome. Let it dry and cover again but this time modeling (cover the right area only) and model it to look three dimentional.
Your other houses should also have shadows on the right side and light (leave alone) on the left. I agree with Doug that your boat should be darker especially on the bottom area.
Have fun and please consider the above for what it's worth. Just enjoy yourself!