Fellow netbuilders I really need your help with this one.

I understand that content is king along with backlinks. My question deals with more then that.

I also know I am going be going up against some really big hitters with my new site. For me this is going to be a battle between David and Goliath.

I am hunting for the Achilles' heel.

Please, help me brainstorm.

How do you find weakness in your competitions site and turn that weakness into your benefit?