Practicing/Movement
Practice in single player, a lot. Even before you play in multiplayer. Learn to maneuver your tori on your own, before you go around kickin' heads. Try to move your tori as if it were you in real life. If you're playing in single player on the default mod, change the engage distance to around 250 or 300 to give yourself some space. And just try everyday to move better. Look at some replays in the replay section and study their replays, you'll most likely figure out movement eventually.

Dismembering Smoothly
After figuring out movement, you'll need to get the hang of kicking and punching uke. To do so, try to move realistically and quickly. To dismember uke, you'll need at least 30.00 speed. To view your speed type in /sm 1.

When punching, contract your elbow, and swing that hand away from uke, while keeping your feet in some kind of stationary position. Preferably try to keep the foot, opposite to your hand, in the front, and the other foot in the back. Then proceed to bring back your front foot, and push the other foot forward while keeping them on the ground. With your hands and body, swing the opposite way you started, and contract that pec, and hold the contracted elbow. Doing the opposite with the other hand for now. Space until your punch is a little centered with uke. Not completely in the middle, otherwise your punch will miss, or not be as powerful.

Here's a replay with a pretty basic, smooth-ish punch.
Basic Punch

Notice: I dip low in this replay, rise up and line up with uke, then finishing by snapping my joints to create a punch. Also, try to relax your whole arm on a punch, or at least the wrist and elbow, right before you touch uke. It makes it much easier to punch.

Hope this helped!