To unlock the More practice trophy in A Plague Tale: Innocence, you will need to complete the aiming training in Chapter 1, "The de Rune Legacy".
After you complete the training intro in Chapter 1, you will be in a stable. Turn right from where you are and talk to Theo, the guy who that is using a shovel. He will inform you that has set up more targets behind the stable. Go to through the tunnel to the right of him and you will find an area with pots placed on top of barrels. Destroy all of the pots and the trophy will unlock.
You will find the exact location in the video below (credit to Trophygamers on YouTube):