I like 1 2 and 3, BUT the background in #2 is distracting (Clipboard on the fence especially).
But what really am surpised with is that the noise seems so high in some of these, considering its taken with a D50 i'm really suprised, Was your ISO set to 1600?
Good shooting Brian, these are well done. Some look as though they were tightly cropped in post-processing, but not bad at all. Keep shooting, if it was fun today, wait until tomorrow because it only gets better.
Brian, once you figure out how to adjust the ISO, try reducing it to 200 (your lowest setting on a D50) if the skies are sunny. If the skies are muted due to overcast, set the ISO to 400. If we can help, please don't hesitate to ask.