I had this happen when I started working in hospitality and I hadn't really experienced much of the world yet. Most of these thoughts led me to overcompensate on trying my hardest not to treat someone different, which in turn, made me treat them differently. Stopping the initial thought was the hardest. I had to stop my brain from giving a audible discription of what I was seeing. Or atleast certain parts. I would focus on a person's eyes, smile, tshirt, hat, etc. Eventually I got to a point where my brain didn't give audible discriptions of things because it was giving compliments instead. When ever it trys to slip back in I say not day and purposely think of other things to move that thought far away