Are there some set techniques?
like using social media?
slut / creep shaming.
Most Helpful Girl
Girls have various ways to bully others, mostly it's psychological warfare (verbal harassment, talking people in to be against you etc.) mostly girls like to gossip so they like spreading rumors as well, of course slut/creep shaming and nerd/unpopular people shaming goes too.
Some girls can be really mean, sure male bullies will beat you up or push you, but girls will turn everyone you like against you... because they can. And of course don't underestimate a girl's power, she can simply beat you up too, if she's up to it.2