Love the reflection. The blue-ish tinge gives it the feel of water. Here are some things you could try (totally up to you, there is no wrong or right in art)
For the reflection:
Play around with is the ripple filter (under Filters --> Distorts --> Ripple...) to displace the perfect reflection (unless that's what you're going for).
Also, you can give it a bit of perspective using the perspective tool and then stretching the bottom corners outwards.
For the trees:
You got the position pretty nice. I would just try adding a dark shadow behind the leaves to give them a bit more volume and then add as much different green colors as you can to break the flat single color.
Lastly for the mountains:
The edges are really sharp so they kind of steal the focus from the reflection. Here you could try a gaussian blur (under Filters --> Blur --> Gaussian Blur)
Keep at it, you've got some real potential
