I would avoid caffine before a trip to the range. All guns are different. Ammo is different.
Experiment with different brands of ammo when they become available to see what your gun likes.
You might consider buying a copy of Successful Shooting by Bill Pullum & Frank Hanenkrat. I've had that book for years & it's still a go-to reference for me when I get off track.
Crime Control. NOT Gun Control.