If you’ve shared passwords to things like Netflix, HBO Go, etc. with her, change them all to something like “lauraisacadaverouslayandadumbbitch.” (Laura’s a cadaverous lay and a dumb bitch.) Then text her and tell her she can continue to use them if she’s cool with typing that password in. Change it again a day or so later.
If you know what their email is sign them up for all of the political newsletters that you can find.
Fire up Photoshop and load a picture of the two of you together. Put a circle over their face with text on the inside reading “YOUR FACE HERE.” Make it your profile picture for fucking everything, and post it to Instagram and tag him/her in it.