1 - The most important: Write it in your bio.
"I am sarcastic", "Fluent at sarcasm", "Sarcasm is my 1st language" or anything like that. So people know what to expect. People need to know in advance that sarcastic stuff is coming so they don't get surprised, sarcasm is something that you always have to tell beforehand about.
Like "I'm gonna be sarcastic now : *insert the topic here*".
2 - Sarcasm equals to being rude, just be rude in a *nice* way. Sarcasm has nothing to do with being funny.
Sarcasm being funny is so nineties and the nineties are not in fashion. And we don't care about fashion even if they were.
When you are
rude sarcastic, add one nice word in the rude sentence and there you go - awesome sarcasm! "Your hair looks like a nice pile of shit, haha" is a very advanced form of sarcasm, because the word "nice" in it makes it so. They know that shit is not nice, duh!
(A simplified form is "You look like shit". It's counted as sarcasm, if the person's bio says that the person is sarcastic (make sure that the bio is visible on the side of your blog / avatar or on your signature)).
None is allowed to get offended, because it was only sarcasm.
3 - Write sarcastic articles and comments.
They may include anything where you can use your sharp sword of words. You can bash the old fart Brad Pitt's nice beard, Justin Bieber's whole nice existence or tell that Miley Cyrus looks like a nice wh0re, or that an article by another writer that you just read was some nice piece of poo.
4 - The old type of sarcasm shall not be tolerated.
Nope. If you read someone using the ancient form of sarcasm and typing things in that you don't like, screenshot that and fill in the butt hurt report. Because no one finds that type of "sarcasm" funny.
Pictures: Tumblr, memegenerator