Without knowing your manager personally it is hard to tell what he wants to hear.
But I think that he expects you to tell him about your accomplishments which go beyond what is expected of your old position and would be fitting for someone in the new position.
Think about extraordinary achievements you accomplished in the past year and additional responsibilities you took. These should be things which set you apart from other candidates for the position. Focus on what advantage these had for the company, not how much of a personal sacrifice they were for you.
"I worked 1000 hours of overtime to finish project X on time. My wife divorced me, I had three heart attacks and my bowling club kicked me out, but I am happy to do this for the company." - so what, you want a medal?
"When I took over project X it was far behind schedule, and most people expected it to fail. But I manged to rescue it and completed it on time. This saved our company a quadrillion dollars" - Great job, you might be suitable for something greater.
Be careful though to not overstate your accomplishments. Stay honest and realistic. "I fixed the soda machine by kicking it really hard. This increased the motivation of everyone on the floor, rescued morale and has saved our company from impeding bankrupcy. So everything anyone accomplished afterwards is practically because of me." ...uuuhm... I think it would be the best for all of us when you would continue your great work in your current position.