Never let the bully know that they or their actions are affecting you.
If you are getting bullied, tell someone or get help with the authoritative person.
When someone bullies you, take your stand and show them that you too have self respect and that you are not going to tolerate such kind of behavior.
Most of the time bullies are suffering with internal problems and are reflecting their own emotions. Sit with them and know their situation and give them a helping hand.
If replying back to bullies, reply humoristically or laugh it off so it seems that you don’t take them seriously by putting them in an awkward position.