Before flying to Africa I practise at the range , shooting in every positions at 50 and 100m.
But the best training is the real thing. The driven hunts season begins in end october and ends the 1th february. To shoot at running wild boars (and sometimes roe) I am using one of my 375HH. Yet when hunting from a treestand, I am using a 375HH as well. This enhance my ability in a very real situation.
There is the test used to qualify PHs too. 2 clay-pigeons are set on the ground, the distance between them being 10m. The wanabee PH stands at 25m with his back to the plates. At a signal the wanabee has to turn and shoot the 2 clay-pigeons in 2 seconds. A funny excercice.

For plain games, long distance shooting is fun too. Set small balloons at 100 and 200m (even further if You want). Then it's fun to shoot them in whatever position and cadence You fancy. Every hit is easily seeable, no need to haul and check any paper target. That's the way we check our rifle at 200m prior to going shoot mouflon and chamois in the Alps mountains.

But sure the best way is John's. The most serious and efficient ay is Dan's. The most incredible are Erik's and Boomer's.