You have to understand whom you want to address and why. If you find a real lady she does not want to play games, I assure you. Generally women hate playing games. We don’t want men to fake, to use tricks, to wait a little longer to respond because you think that we think that you think (…you see? This is mental masturbation, it might work but is does not work with grown ups or people with guts, so better forget it. When a man thinks “A” usually a women in the same time thinks “ABC446gSIEHFNI&%ß…” so please be kind and don’t drive us insane with games. Thank you).
If she takes, say, half an hour to reply back to your initial text, and you reply within a minute or two of her response, you come off as very needy. (You also come off as a bit creepy, like you were just staring at your phone like some kind of Fatal Attraction-type character, just waiting for her to answer you, and when she did, you answered her right away.)
Callback humor is talking about something you two discussed that was either funny or interesting. If it was something funny, you’d text her about whatever it was that made you laugh. Any type of text would work. All you’re really doing is bringing up the good emotions that were released with whatever that subject was that caused the humor, thus making her recall a pleasant memory and associating that memory with you.