I think what people are saying is that although you need to "be yourself", yourself needs a little upgrade. Get some confidence when dealing with girls. Smile, loosen up (you always stand very still), and at least try to look like you're having a good time. Your body language will communicate much more than your mouth ever will. Practice practice practice! (I'm still practicing!) People will notice, and will respond. And that will build your confidence so you can do better next time.
That's when "not caring" comes in. You'll be so intent on having a good time, just hanging out with people, that you won't hardly notice if a girl starts fawning over you.
And that's when you've got her in the palm of your hand.
