Right-handed pitchers have a “margin of drift” that goes from right to left. To recognize what that is on game day is to witness this “margin” during your bullpen session.
Focus on a target, on the player/catcher that’s assigned bullpen with you.
Start off by giving yourself 40 feet at first to hone in on your target.
Use the 4 seam fast ball grip, with the following adjustment to your grip:
= make sure the curved part of the seams points towards the 3rd baseline. Now slowly rotate that curve just a bit … like a steering wheel, a little more around towards 1st base … but not too much.
when releasing the ball, release it at cap level, but bend at the waist before your release. Most pitchers that have control problems release then bend … in other words they get the process backwards.
keep your head in the pitch totally. Don’t look away, glance down, or take you eyes off your target at any moment.
prior to striding forward, try stretching your glove arm out, pointing the fingers and thumb of your glove hand down, then rotate towards the first baseline. Then during your final release phase of your pitching cycle, your glove arm/hand will do the rest without your even thinking about it.
My suggestions are very basic, and without actually seeing what you now doing, it’s an educated guess at best. But heck, it’s worth the try.
Now I’m assuming that you’re getting a good night sleep, your not tired, you don’t have eye sight problems, or just got out of the hospital after a sky diving accident, crushed by a Mack Truck, and so on. Don’t laugh … more than just a few people that have visited this site and asked … “hey, can anyone help on this…?” only to find out they’ve just been released from a total body cast, or something similar … a thing they neglected to mention during their initial quest for help.