C&C per req:
1. Good use of leading lines; they draw the eye directly into the centre of the image, however there's not a lot of interest there. Technically the exposure is fine, but the use of a polarizing filter and a graduated ND filter to darken the sky, increase saturation and contrast as well as remove some of the reflections from the water would have made this a much stronger image.
2. Despite good use of selective focus, the bright, lightly coloured background is rather distracting. I would suggest focusing in on just a couple of reeds, preferable against a dark background.
3. Again good use of leading lines, but again, no definite subject to hold the eye. This image is a bit of an exposure challenge with the brightness of the snow and the [relative] darkness of the metal railings.
4. Nice; good exposure. Perhaps a tighter crop to make the birds stand out more in the image. Again, a polarizer would have reduced the reflection of the water and increased the saturation.
5. Very nice, but suffers as a result of the bright white of the snow in the background. As a general rule, darker backgrounds are better than lighter ones. A simple change of position to your right may have helped greatly.
6. My favorite of the lot. I would take this one back into the pixel room and crop just a little more tightly on the main leaf, as well make it just a little darker and perhaps boost the saturation a tad.
Overall, nicely done.
Just my $00.02 worth - your mileage may vary
~John