If you're physically unattractive and you meet someone in real life, you still get to introduce yourself and give them a glance of your redeeming qualities. Online, it's "flawed you" against 100s of perfect looking guys. You don't stand a chance.
As an average-looking guy I've had no trouble finding women to date online. The trick is to not have a "trick" and just be a decent human being who wants to have mutually fun conversations with people. Make more friends than lovers, like anyone with their head on straight will expect of the world.
(edit: this is just relevant to the first half of the comment)