For an entry level agency position most individuals now have a Bachelor's or Master's Degree from a recognized university. Many have commerce or business degrees. A sense of humour. An inquisitive mind and an interest in a wide variety of topics. Excellent verbal and written skills.
Persistence is the best answer.
In any given year there are very few jobs available for the number of applicants. Some industry leaders have estimated that fewer than one in twenty applications are successful in securing an agency position.