Some of us have trouble with this. It goes against our grain to annoy people. Once you get to doing it though, it's loads of fun!
(DISCLAIMER: Don't listen to anything I say. Being obnoxious is a really bad idea)
Here are some tips.
Quit caring what people think. People are going to stop liking you.
When there's a moment of silence, burp really loudly.
Talk back to cops.
Enforce group hugs.
Eat onions and garlic before going to dental appointments.
Tell people they're wrong even when they're right. Make up facts to support yourself.
Set the world record for most parking spots taken up by one car.
Kick people's dogs.
Become a hair stylist. Give everyone mohawks.
Put super glue on chairs.
Drop gum in the subway.
Act like a terrorist.