I am terrible with names IRL so this just is what it is. I'm sure if I had read the books and read the names 100s of times I'd be better at recalling names.
But I didn't, so now I use terms like Khaleesi, the Grandma, Redheaded Wildling, Fat Night Watch Kid, and Peter Dinklage/The Imp (these are interchangeable) when referencing the characters.