Fail to make eye contact
Look at her when she's talking to you, even if you're uninterested in what she's saying and you're not really listening. Zone out, daydream, think about your intramural basketball league tournament, but continue to make eye contact. It would be great if you were actually listening to her because she will test you on this later, but as long as your gaze is in her direction, you'll give her the illusion that you're present. Conversely, you could be listening to her intently, but she won't know it if you're staring at the television.