I believe it's both Practice *and* Talent. Talent with no practice yields poor results. Practice with no talent may yield OK results after enough practice. Of course if you are talented you may need to practice LESS to get same or better results with maybe more original ideas/flair. And if you are talented and you practice loads, then you'll be very sought after.
See this about practice:
http://greyaliengames.com/blog/a-simple-exercise-to-get-better-at-press-ups/
See this about practice:
http://greyaliengames.com/blog/a-simple-exercise-to-get-better-at-press-ups/