I'll put my most humble opinion in...
#1. Focus and Depth of Field are my main issues. There is nothing focused on to draw attention to. I am going to assume that the main object here is the pillars in the water. That being said I would have shot this from a different angle with the water as the background to them rather than the other shore line. They are getting lost in the background. Also I would have cropped out quit a bit of the top and left of the shot. Cropping as alot of people will tell you is as much an individual expression and style as any part of photography so take that cropping advice with a grain of salt. But to me there is just way to much in the shot. Could also be lighter.
#2. First off I love this shot. Best of the group imo. However, There is a slight focus issue. This could probably be taken care of in PS or whatever you are using for your PP. Again I would like to see it lighter. Good things about this are your crop and point of view. I love how the driftwood leads from the kid to the background. Some may not like the pavillion or whatever the building is in the background, but I don't think it is to much of a distraction to worry about.
#3. Again to dark, the sign on the left side is alittle distracting, ans well as the partial banner on the right side. Might try cropping out the banner to just read "Farm" so that it's not like we are missing something. Overall just nothing there to say "Wow!" about.
#4. Another nice shot...still alittle out of focus and dark. I would clone out the trashcan or what ever that is beside the kid.
All these are to dark for my taste. It may just be how you are converting to B/W or it may be what you were going for, I just think lighter would be better.
I hope you don't mind but I did an edit for example...
Your original post
A quik 1 minute edit...
Photoshop CS3
Level Adjustment 6/0.91/201
Unsharp Mask 196/1.0/4
Gradient Tool-Colorburn @ 10% opacity
Crop
Not saying my quik edit is a prize winning job, but just to show the difference in lightness and focus.
Keep up the good work. Hope to see more of your stuff soon.