We rarely use a full size "bat" or a full size "ball" when doing soft-toss. This is done to intensify the drill and the skill being taught. Position your self to the batting side (right for right handed batters) and ahead of the batter. Toss the "ball" at the hip of the batter. You want them to impact the ball in front of their body. This is the "contact point". The toss is important!! You do not want an arching, ugly type of thing, unless you are playing the old man's game of "slo-pitch", if so, you are on the wrong home-page. The toss should be crisp, but not too fast and out in front of the batter. Practice this to get it correct.
We use soft-toss to teach and reinforce the proper mechanics of the swing. Make sure your batters are 1.) pivoting correctly and early enough. 2.) rotating their hips with an explosion toward the ball 3.) unlocking their shoulders, elbows and wrists in sequence while throwing their hands straight to the ball (watch for hands dropping and correct this). 4.) Watching the ball all the way to the "bat" and continuing to watch the "contact point" after the "ball" has been hit.
The proper stance is essential. It should be a balanced stance with 60% of the weight on the back foot, eyes level, bat in launch position (not rapped behind the head), knees slightly bent, and door-knocking knuckles lined up. The stride should be a short, smooth lift and move type of stride. At impact with the ball and at follow-through, the body should be in a slightly curved position toward the ball (inward "c"), this insures that all the weight and power went in to impacting the ball.
We have used many things for "balls" and "bats". To increase concentration on the ball, try using tennis balls, practice whiffle golf balls, coffee can lids (plastic ones like frisbees), but my favorite (and the players favorite) is to use black-eyes peas. We start hitting them with a full size bat, but quickly move to using a "thunder-stick" or a home-made "bat" I made which is about the same size as a "thunder-stick" but with less weight inserted in the end. I feel we are trying to teach muscle memory and too much weight teaches a slower swing, but others think diferently. During warm-ups before games, I always hit the peas and them some LOUD, regular sized softballs. These are the hard ones and they sure turn some heads! The girls love the looks on the opposing teams faces when they hit these loud balls. We hit into a portable backstop so there is no time lost chasing balls.
One of my favorite drills is the "High-Low" drill with the practice golf balls. I hold 2 balls in my hand and toss them into the "contact zone" and call out either "high" or "low". The player must hit the corresponding ball. I tried it once with the black-eyed peas and was quite successful.
If the batters start to "cheat" on soft-toss drills, I hold 1 ball in either hand and rotate them (like juggling) and toss one up. This way they do not know when the ball is coming. They all hate this, but it works!!