Good avise from Beng and Coyboy!
We used to break out the clay pigions before deer season. Just like anything else a little practice goes a long way. That and one of the local ranges held a running deer shoot before season every year, they had a plywood deer cutout they run back and forth on a cable=Great way to practice!
The one thing we learned early about shooting at running deer was to do a good job of following up after any shooting. Dont asume you missed or hit=check and double check every time! Most crumble when hit but if shot in the boiler room they can go a ways without much sigh of being hit.
Never liked to start shooting at a running deer but once I started the gun was emty or it became unsafe to continue before I stopped and all where inside of 100 yards and closer to 50 yards.
We tryed the rolling tires thing but it gets to be a lot of work rolling the tires back up the hill

That and to be safe its hard to find a spot where the guys rolling the tires are out te line of fire at ALL times......We had one spot with a berm that totaly protected the rollers.