I think you're off to a good start.
Try controlling your color temperatures more. Trees in particular tend to be more warm where the light source touches the leaves. So the browns mixed with a touch of the green you're already using at the top, and more green maybe mixed with a violet mix at the bottom. The background's tree color might need a warm glaze because the colors match the foreground. Makes depth perception hard to read. To make this seem more alive, there needs to be a more established light source.
Just a bit more to go! :3