Toilet picture on door
Paint the door a different color than the surrounding walls in the hallway
Leave the bathroom door open so the toilet is visible
Keep a light on in the bathroom
Have a light on in the hallway or motion sensor lights so your loved one can see to get to the toilet at night
Reflective tape is an option to highlight the path to the toilet
Make sure their path to the bathroom is free of any obstacles and anything that could be mistaken for a toilet
Install a seat riser so that the person doesn’t have to bend down so far to sit on the toilet (I appreciate the taller toilets!)
Install a black or red toilet seat so that it shows contrast with the floor and surrounding area and helps with depth perception. You could try a light green toilet seat as green is a calming color and it would provide contrast. You might have to try different colors (stay away from patterns) as a color may end up seeming like a hole and you don’t want that. See a few color choices in the links at the bottom of the post.
You could try coloring the water
Flooring should contrast with the toilet so that the toilet is visible
Avoid shiny bathroom floors. Dementia patients may think the floor is wet and will avoid it.
Putting a non-slip mat at the base of the toilet might help in distinguishing the floor from the toilet but that’s a potential trip hazard so that may depend on how mobile your loved one is.
Wear clothes that are easy to pull on/off however if your loved one is going to the bathroom everywhere (and not in the bathroom) then you might switch to adaptive clothing which would require someone’s assistance.
Remove any other objects that might be mistaken for a toilet such as a wastebasket, a plant or a hamper
If mobility is an issue in getting to the toilet in time, put a portable commode beside the bed
Reduce the amount of caffeine they consume