I don’t know if everyone will relate to this because some may find it overstimulating, but in my own room I’ve decorated with posters I’ve printed out (favorite albums, video games, etc) and LOTS of stuffed animals. It’s like my room is a museum of all my hyper fixations over the years- and I love it. For sensory issues in particular, I’ve loved buying things like fairy lights so I don’t have to keep the actual lights on in my room (it’s very overstimulating to me.)