Take the commercial apart and see how it works
One of the ways to improve your skills in any field of expression whether it’s visual art, poetry, songwriting, filmmaking or writing is to analyze the work of the masters in each medium and discover the principles that make the piece successful. Will it work for radio commercials? In my experience, yes. Whether you use it as a way to break writers’ block, or as a continuing method to improve your writing this exercise may be useful.