Is it possible to improve my singing riffs and runs?

I can for sure do riffs and runs well. But i want to do them
amazingggggg. like this girl:

http://www.youtube.com/watch?v=T6Uy4qj72MYfeature=relmfu

ahhh shes amazing. But yeah i can do riffs and runs well. But she's
flawless. Do you think if your already halfway there to doing it as
well as her, is it possible to work your way to as well as her?