Hey Bill,
That definately could be an issue... I always try to shoot with a tripod to get the sharpest image possible. However, when you are moving like that it is good to adjust your settings to get a shorter shutter speed, by either opening up your aperature or increasing your ISO... not saying thats always good to do though (but its better than not having the shot?).
I will say that focusing is really hard unless you have great eye sight... when it comes to a scene like this. If you have Live View, use it! I remember with my 30D having photos slightly OOF that I thought were sharp, but now that I have Live View on my new camera it never happens unless I caused the camera to shake somehow.
My biggest suggestion is just to read and then re-read your camera's manual. I think I shot for about 3 years with my 30D before I actually read it... and my photography improved exponentially after that! Besides that... just keep practicing, you seem to have a good eye so keep it up
!