Re: First Landscape Painting (X-Posted in Compostion)
The best way to understand how shadows fall is really to observe them in real life. Next sunny day, go out and spend some time just looking and noting how shadows fall depending on where the sun is in the sky. Maybe do some quick sketches too. EVERYTHING has a shadow, therefore in your painting, the tree on our right should also be casting a shadow.
All the shadows must fall in the same direction. It would not be possible to have the horse's shadow falling behind it and the tree's shadow falling in front of it.
If you are wanting to make this a sunset (or sunrise) painting, then the shadows would fall more like what you have painted for your spruce tree, because the light is coming from the other side of it. The horse's shadow would also have to fall in the same direction, as would the shadow of the tree on our right.
Also, some light purples or violets would help the pink sky blend into the blue sky a bit more gradually.
I think you're learning lots from this piece, no? In my humble opinion, at some point it might be good to start on a second painting, this time using a photo or a real life scene as your reference image. Then you can apply what you have learned, and use this one as a measure of your progress. Just my 2 cents though! I'm not saying "give up" I'm just saying don't get hung up on making your very first landscape perfect. It will only frustrate you, and I speak from personal experience, haha.