takes a lot of practice to get super clean welds....looks like your using a lot of filler too...
Like monkey said
"Keep yourself moving, and do the same thing every time. It's like a ritual, if you do the same thing.. puddle, fill rod, move, puddle fill rod move.. it will look the same."
Also, if you rest your elbow on something like your leg to keep it steady, this will help with the "uniform" look. Keep it up!
Also.....search for how to videos on the net, came across "Tony's Welding Series" by looking on google videos.... http://video.google.com/
heres a pic of some work from our resident fab guy **WARNING** WELD PORN***