The key to the perfect cookie is the batter, and I mean BATTER not dough. It should make you wonder if you put in enough flour. However put it in the fridge for a little while and it should firm up a bit.
ALSO the chocolate chips, they need to be good chocolate...and people...just 'cause Nestle says their the best doesn't mean they are. Get the good stuff it's only a dollar more.
The vanilla, it HAS TO BE REAL! This is also why you need to use good chocolate.
Behold...

A perfect chocolate chip cookie.