The best way to work with these visualisations is by bringing them to mind as much as you can.
I suggest always setting aside 20 minutes or so every day.
Use this time to ground into your body, connect with your baby, practice breathing techniques, affirmations, and any other mind/body techniques or practices you’re using.
You can also use this time to consciously bring the visualisations to mind.
From week 35 of your pregnancy, you should aim to spend some more time each day with the visualisations.
Perhaps on a long walk, while you’re having a bath.
Just keep finding those quiet moments where you can really bring these images alive in your mind.