Wollaton Hall

So this basically the issues here are the colors and your use of the media. The composition is fine and the reflection and water is actually quite nice. (although what are those beige colored things like squarely in the middle?) The sky and water are really way too blue and more mixing could have been done. There is almost no shading in the trees and the oranges and reds stand out alot for that to be natural. There is a lack of detail in the trees which could work if you at least paid more attention to color and lighting. Overall, try sketching first to get the lights and darks down and then try to learn a bit more about color and painting.