Transforming a friendship

I've had this story idea in my head for a couple of weeks now about a guy and a girl that have been friends since childhood, even though he is a few years older than she is. They have been with each other through every one of lives little adventures but now he is starting to see her in a different way. How can I transition a friendship into a romantic couple without it sounding like something that has been done over and over again?

(Posted Sep 23, 2016)