台湾樱花湖

This is based on a photo of a Taiwanese cherry Blossom lake I made using Cycles Blender. Some parts are quite off but overall the original image is somewhat correctly modeled. I don't know much about Lighting and also i am just a beginner(actually a high school student) so please suggest any techniques that i can use to make my blends better. Also it has a very large file even while compressed so i'am looking for a way to make it smaller and a lot of thanks to you people who can help me. Please feel free to give your opinion and regards about my Fanart.