I'm with you. I made it to hardware architecture in undergrad without ever pulling out a book to study. Then I had a rude awakening and ended up on academic probation and failed a few classes while I figured out how to study. Luckily I was friends with a couple of girls who were driven (finished school with 4.0s after finishing HS with 4.0s, etc...) who basically taught me how to study. They also showed me the effort required to really learn something.

I think in the end, the slap in the face came at the right time and made me more capable later. No matter how smart a person is, there are things they do not know and have to go learn. Learning how to learn it skill, and like all skills it takes practice.