By wall drill I mean starting from the set position with the outside of your pivot foot and your throwing shoulder against the wall. Cross your arms in front of your chest. From this position, execute your lift. If you bounce off the wall, your first move is backward--which is what we are trying to eliminate. This drill will teach your body to lift while also thrusting toward home plate and away from the wall. Focus on getting your maximum lift and getting front side distance from the wall. Do this for 30 clean reps per day. Progress from arms crossed to an explosive hand break to equal and opposite position. Again, make sure your throwing hand does not touch the wall and do this for 30 reps per day. Then progress to dry throwing from the wall.
I like to have guys try to plink cans with baseballs. Put an empty soda can on top of a tee. Position the tee in a specific location and see how many times out of 20 tries the pitcher can knock down the can.
Down and Backs (aka 2 minute drill) Line up on the baseline of the basketball court in your gym. Have the pitchers run all the way to the other end of the court, touch the far baseline with their hand and return to the starting point. Repeat 9 more times without a break and finish in under 2 minutes. Run one additional length of the court for each second beyond 2 minutes that the drill takes. They will be some tired puppies at the end.