It's not how good you are, it's how good you want to be.
A graphic designer, David Airey, suggested this book on his blog, and I first read it when I was a 1st year at university.
Reading this book might be such a cliche thing to do in this industry, but it actually says cool things, and I think I literally read this within an hour.
One line I still remember is that
It's not what you know, it's who you know.