Know which poses are considered passe
There are certain selfie poses that became wildly popular and are now well past their prime. You can still contribute your own examples to the mix, but do it with a little self awareness so people know youre in on the joke. Notable choices include the infamous duck face, muscle flexing, pretending to be asleep, or pretending to be caught off guard by someone else.
The duck face is a combination of puckered lips and wide eyes, originally made famous by Snookie and friends. Do it at your own risk.
Taking a selfie and pretending that someone else took it is hard to pull off. There will be some clue in your posture or actions that will give you away and open you up to criticism. If you do it with a slight smile or a wink, people will realize its an intentional setup.