Rule # 1:
A selfie is only a selfie if (surprise) you are taking a photo of yourself. A photo taken by your girlfriend or co-worker isn't a selfie. So take a few minutes to acquaint yourself with your phone's buttons. The pros use the top volume button to take a picture instead of the actual camera button.
Rule # 2:
Stage your shot. Make sure there's something cool or interesting sharing the photo with you, like a plane, a limousine, a baller hotel room, the backstage area at a fashion show, or your really cool friends. Just go easy on babies and animals.
Rule # 3:
Find your light. Make sure your face is being lit in a flattering manner. Avoid being backlit unless for artistic purposes, in which case that's so creative!
Rule # 4:
Smile, squint a little, show off your abs, wave, give us a peace sign, or pull your best "blue steel." Whatever you do, do something. Nobody wants to see you looking constipated alone in your office. Which leads us to the last selfie rule.
Rule # 5:
Have fun. The most important lesson male models can teach us is how to live our best lives. Say, for example, you're at an after-party in a hot hotel. Go out on the balcony with your friends and capture that moment. Then go eat a shitload of tacos and tweet about it.