This is a really great drawing! So ok let's start!
Clothes: There were some shadows missing, like on the white shirt and for the pockets.
Forest: That forest doesn't look straight, it is like going back at that didn't seem right in my eyes. The next thing is that the grass need to be lighter then the trees, but it seems you have them in the same color. Now if you want this perfect then I can say that there are no shadows for the forest.
Clouds: The clouds need to be more puffier. Now the clouds are a bit too flat.
I am not spotting any other small mistakes. There might be some really minimal mistakes but i don't see them! ^^"
Good job on this Lord! ^^ I am proud of you!