Feedback would be betther if you posted less and added a question.
1 seems a bit soft. Likely because it is focussed on the sand behind. Please post your exif so it is easy to comment. Says f4, 1/1000, 45mm, iso 100. Obviously the 1/1000 is and iso100 is good. You should turn up the fstop to f8 even if you have to go to ISO400. I would crop the right hand side off just to focus the viewer on the action and create one central subject - the game. It would be beter seeing the face of the hitters.
2 nice lines, nice colors. It seems soft on left. The man on the left is distracting. 1/125 is good for this still picture. f4/24mm suggess you focussed pretty close. I would up the fstop to f8 for more depth.
3 very nice scene. Crop so that Horizon is closer to 1/3 down and it will improve. I would crop 1/3 off left so the guys are not centred too. (it would be nice if they were walking into the sun but that would have to be 30 s prior. Using a bit of shadows / hightlights would improve.
4 needs her legs. The blue background and legs are distracting and I would crop them out. Seems soft and I dont know where you are focussed. I would have shifted left and gone portraits and got her feet and mroe concentrated birds. Face would be nice too.
3 is my favorite and with the crops suggested above would be greatly improved.
Hers's another shot from the same series #4 was in. This one is at 32mm, F4, 1/125 sec, ISO 100.
http://hollywoodwebs.com/photos/BirdGirl.jpg
I would love to lose the dark canvas material in the background, but doing so leaves me with most of the flying birds cropped out, and with the girl's head right at the top of the frame.
CementJungle: You asked "All your comments mentioned softness. I did in fact use PS smart sharpen a bit and thought I had gotten the best I could without causing degredation. I was using the Canon EF 24-105 F4 L zoom lens, with a UV filter for protection. Do you think I'm being limited by the zoom (as opposed to a prime) or the filter, or both?"
I am posting it here because it is a good question for all and it is likely that someone else brighter than me will add to the comments.
Softness is cause by i) shake, ii) too slow a shutter speed, ii) too high a aperature, iii) focus on the wrong spot, and iv) under exposure, or v) lack of sharpening in RAW.
i and ii) can be taken care of either by following the rule of thumb - shoot faster than 1/100 handheld, 1/650 for sports, or the reciprocal of your lens (ie 1/480 for a 300mm lens because of the 1.6x factor). Or use a tripod. Also if shooting sports put the focus setting on Auto Servo.
ii) aperature will cause softness if you go above f11 on 1.6 camera or f16 on a 1.0 camera because of defraction. You lens is generally sharpest 2 stops above wide open. So if you shooting landscapes move the fstop to about f8 on a wide angle lens for sharpest.
iii) focus on the wrong spot will cause softness. Always choose your focus point carefully. In the case of the volley ball I would up the fstop to make it less challenging, put it on auto servo. Althernately I would move to f11 and manual focus.
iv) underexposure will cause soft too. Make sure you watch the historgram. Make the historgram closer to right then left but not clip and watch for blinking areas that suggest you move the exposure down. On my camera 20d use press the shutter 1/2 down and turn the wheel to change the exposure when in the slash mode.
v) all raw pictures need sharpening. If you have not sharpened they will not look sharp.
Unless you are really good, the equipment is not the limiting parameter. I have cheap (non IS, not fast) lens and always feel that I could do better with a different setting. And I am happy with lots of my shots. Sure faster lens help but without technique with expensive lens you will still be soft.
I have the 24-105L IS. Your lens is not the limiting factor. Unless you have a poor quality UV filter, it is likely to have minimal effect on the quality of your image.
Scott's points are, as usual, right on. There are issues about your choice of depth of field/aperture but areas within the depth of field should be sharp with your lens, assuming fast enough shutter speed for action, correct exposure, etc, adequate post-processing.
First image is a memory shot; meaningful for the folks there. More interest would be captured with the expression of the team hitting the ball, perhaps by shooting from the sideline. A bit too much of the softly captured man on left in this image.
Second has nice colors, details but does not generate much interest to me. Again, serves as a capture of memories, area visited. The wires in the sky are unappealing. What is the subject you are trying to express/capture?
Three: See Scott S's comments. This shot would not work without the surfers. With them it tells a story, breaks the image from plain but pretty sunset. Re crop.
Five Cute. Better than four. But four has her more surrounded by, immersed in the flock. You've caught some of her expression, relating her to the scene around her.
ditch #1 & #2 - they have no artistic merit (imo)
#3 and #4 have something going for them.
#3: play around with the cropping.... I feel like you could have a more poignant one here
#4: once again, your composition is a weakness... try to recrop in such a way that the position of girl's body gives a more interesting flow to the action. at very minimum, crop about 3% off the left side to remove the bird heads.
