Here`s what I used to do before I went to college. I hope it helps, it sounds like we have similiar setups.
Warmup playing liight catch just to get things moving. Take your time.
Mark of 55
from your strikezone bag with just a line or somehting easy to see.
Place a batting tee (road construction cones work well) on the corner of the strikezone.
Start form 55` and concentrate on hitting the ball off the tee. Do not throw overly hard, but throw firm. Use full mechanics and just work on your release points.
As you get better move back to the 60
6` line and go form there.
Be able to do this with a fastball and changeup (not sure on your offspeed ability) Keep track of how many out of 20 you are able to hit every day.
Do 2X20 form both lines with a 5-7 minute break inbetween sets to let your body recover.
Do this M W F and on T TH (Saturday once your arm gets stronger do the following.
1X10 flatground pitches at a gamelike speed (full mechanics)
2X10 throws at 100% with just a step and a throw
3X10 full crow-hop and throw at 100%
2X10 Throws at 100% just step and throw
1X10 flatground pitches at a gamelike speed
May not be out of a book but it is something that worked for me.
Good luck, and thanks for serving.