First time? Wow, you've got some natural talent then.
Thanks, I picked up Understanding Exposure and have been looking at all the great aritcles on DPS also.
1. Go over those spots with a subtle 'dodge' in PS, but leave them just a bit darker than the naturally lit areas. This is the post process equivalent of using a fill-flash, and if used correctly can definitely improve shots.
Is there an equivalent to this in lightroom2?
Lastly, Something about the bokeh in the shot seems a bit weird to me... It could be that that particular aspect of your lens isn't its strong point, but I suspect there's a fair amount of sharpening going on here, whether in camera, or in Photoshop. Try to keep sharpening subtle, and if more is necessary, separate the "in focus" DOF areas from the blurred ones on a new later, and sharpen only them.
Yes, i tried to sharpen my somewhat out of focus image in lightroom. I had a few more taken at 1.8/f and 2.2/f, but the ball was too blurry to understand the shape.
2. This is just plain a gorgeous shot. It's one that's done a lot, so there's not much 'new' there, but it's so well shot that I don't really care. If I had to nitpick, and I do

, I'd say play around with a slight "s" shape in curves to deepen some of the darker parts, and add a bit more contrast. Here's an edited version of what I mean: I very slightly modified the curves, then took a huge burn brush at 10% for shadows, and brushed over it a couple of times. Then I took Dodge at 5% for midtones and did the same thing.
It's a subtle change, but it added some variation in the water color/brightness and the sky, to make the colors appear a bit deeper and more dramatic.
That's amazing! I tried doing something like that inlightroom with no luck. I'll have to play around in PS and replicate it. I purposely splashed water on the kayak to get the effect, but still turned out dull.
3. This photo seems a bit like a well-shot snapshot to me. Don't get me wrong, it's very cute, and the DOF is nice, but the background isn't interesting enough to really cut it, or clean enough to go for a minimalist thing. If it had been all wall with no corner/door, and more central on the stairs (no bannister), it would have put all the focus on the dog, and I think would be really nice.
I had the same feeling, but couldnt go shut the door or I would have missed the shot.
4. I can't really decide either. The land on the right is hardly necessary, but the tree is better positioned in the first. What bothers me, though, is the angle. The background trees go almost halfway up the subject tree, and that's distracting. I don't know for sure if this is possible given the location, but maybe going closer to the ground with a long lens would help. The longer lens (Longer in general, not necessarily longer than what was used. 75mm 35mm equivalent or more [generally around 50mm on DSLRs])would eliminate that low to the ground stylized feeling, which doesn't suit this shot all that well, but actually being low would raise the subject tree in relation to the background. The last thing I'll say is this: Circular polarizer. If there's even the slightest bit of blue in the sky, and I'm outside, my polarizer is on.
Funny, my cir-pl was on, but I think I forgot about it (just got it) and didn't rotate.
Sorry for the novel, once I get going it's hard to stop! If it seems like I'm calling out everything on your shots, don't take it in a discouraging way whatsoever. If I don't think a shot is worth critique, I won't give it, but these clearly are.