On most bait-casters there is a spot to make an adjustment to keep backlashes under control. The way I got taught was to correct this adjustment with EVERY new bait(of diff. weight) that you use. This as I said should help.
Good Luck and Good Fishing!

"Educate" your thumb by practicing with a weight. Hold the rod at about waist level and press the release with your thumb firmly on the spool. Slowly ease off on the pressure until the weight begins to drop. Practice stopping and starting several times, and then try to let the weight drop almost to the ground before stopping it. This is the same timing you will need to stop a cast before it hits the water (or a tree.) As you get better, you will be able to feather the end of the cast to decelerate the lure just above the water's surface and produce a nice soft landing. Once you get the knack, you'll have far more control than you ever could achieve with spinning or spincasting gear. For accuracy, there's no substitute for backyard practice. Try to hit a 5 gallon bucket. Any bucket contact is good at first, but ultimately, you should be able to stop the cast over the mouth of the bucket and drop it inside. Scoring a few "buckets" will pay off in more fish on your next trip, and you can always decrease the size of the bucket for more challenge. Be sure to try overhand and sidearm casts, as the different grip angle changes the feel. You are creating muscle memory that will eventually allow you to take all conscious thought out of a cast for a moment of pure fishing Zen.

Good advice above... adjust the weight of the lure to the reel by dangling the lure from the rod tip. Back off the reel clutch adjustment until the lure drops when you hit the release. As the lure drops, tighten the clutch until it just stops the lure. From that point, you should be able to use your thumb to control things. Practice, practice, practice.

I taught myself to cast a baitcaster, using cheap mono line and a bunch of it. I spooled the reel with only as much as i need and if a rat nest occurred i simply cut it all off and started again. As you get better at casting you can "get away with" less and less drag on your free spool which will maximize your distance. As for accuracy, its all practice after accepting that the hard you throwing the bait the less accurate it will be. A 2 hand cast is the least accurate and pitching is the most i would imagine.

http://www.youtube.com/watch?v=fZs2vAJp0Ec