Personally I give each character a face, either from a person I know who matches their personality or a celebrity that fits the description, even though sometimes it can be really annoying if the author gives more details on the persons appearance and my character doesn’t fit that lol. I’m very curious as to what other people do.
I just picture them with people that I know in my life. Sometimes if a character reminds me of someone and they will look like that someone from my life. 🤷♀️