When you get it back, set to single area. 3D tracking brings the win for sports. I loved it when I was shooting sports all the time. Literally, I could lock onto a player and the camera would automatically focus on that player as they moved. Friggen beautiful. Works good if trying to photo little animals/kids that are running around. Otherwise single area and as you shoot, look through the viewfinder and pick what you want to be your focus. Never had any use for dynamic area and auto is useless.
Set the servo to AF-C. What this means is that as your subject moves (AKA rovers, jeeps, yotas, etc) the focus will change, keeping it in focus. AF-S is good for landscape photos but really AF-C also works. Lately I've been doing landscape and on AF-C my camera sometimes "hunts" for the focus. A lot of times I end up setting it on manual. Which is fine. AF-A is useless.
Looking at your photos, focus seems to be your biggest issue and I think these two setting will help you.
These setting are more "manual" and less automatic. However once you become familiar with them then you'll get better photos. Also I just checked groupon for Columbia, SC. They have a couple for photo classes. If you want to get better, this is the best place to start. Friggen $25 for a jump start on getting what you want from a DSLR. Frankly, I practically killed my old D70s just learning how to take photos and figuring it out. You gotta shoot A LOT. Also as I am being reminded of, to stay sharp you gotta practice.