One thing I spotted in this last study: you put in the brightest values seen in the reference, omit the darkest ones (mostly in between the trees, along the shore). That takes out some of the depth in the picture.
You could try different brushes, too; your studies have a very distinct shape because of the horizontal flat brush you're using, which is good for some areas but very limiting in others.
Would looking at looser landscape work help you better, perhaps? Something like Sargent's watercolours:
Keep going! :)