Hi there,
1. I really like the composition of the first one. The three boats in the foreground give the whole image depth.
Maybe the saturation is little too strong but that's really personal preference.
What I was wondering is what kind of lens did you use for your shots?
In the first image I can sense some color fringing or chromatic aberration especially on the very right in the upper corner where the tree branches are.
The mood is nicely captured.
2. Nice composition but there I'm missing a some more color intensity to enhance the mood. I think these shots would be a great opportunity to test some HDR processing. Scenes like this I would bracket -1/0/+1 or -2/0/+2 and see if you lighten up the foreground a bit.
3. I think that shot was taken too wide. More zoom onto the two birds moving in the mist would have nailed that image - they seem a bit lost. Exposure is fine.
4. Hmmm, not too special IMHO. Composition is not working well here. No. 3 would have been THE shot.
5. Nice colors and focus (as much as I can tell from this preview). I'd framed this one in portrait and not horizontally with a tighter zoom. Maybe move the subject a little away from the dead center, especially is you have more out of focus background to the left or right.
6. Interesting. Somewhat unreal colors. The black and white horse is killing the picture. It doesn't separate itself much from the background. Not your fault

. Kind of weird that the forest in the foreground is so extremely red. Not sure what you did in post and if it actually looked like this when you shot it.
I have no idea where you're coming from and if you were shooting film before but you're doing well with your new D-SRL. Exposure looks good - I just get a funny feeling about the lens...
Keep going! Good luck!