Apart from over-exaggerate the supposed illness, that is.

Another is do not brag about it on your Facebook page.

Kyle Doyle, who works at telco, AAPT, did, and got busted by his boss.  He took a sick day after a big night out, and his boss refused to approve his sick leave.  Kyle disputed this, claiming that the leave was for medical reasons, and asking for proof from his manager why he didn’t consider the sick leave valid.  His manager sent him this:

Totally busted, Doyle replied to the boss:

 “HAHAHA LMAO [laughing my ass off] epic fail. No worries man.”