All these fields require ability to communicate extremely well. Another vital thing is creativity.
These fields are highly competitive and to be successful, there are many other things like dynamic approach, flexibility, long working hours, interaction with people, ability to take risks and face competition, self initiative, thinking and imagination, commercial awareness and so on.
Leadership skills, organisational ability, good negotiation skills, networking, decision making, and tactical approach are required too, especially, for event management.
Fashion designing also requires design ability and graphic sense.
Advertising demands commitment, imagination, analytical thinking, self-confidence and enthusiasm.
Advertising and event management, generally, do not require any specific degree. However, there are related courses being offered by some institutions. If you want to do any specialised course then join one, otherwise, graduation in any stream is enough. Studying related subjects during graduation would be helpful though. Getting work experience is vital. So, you would spend long time as a trainee.
You can study visual communication, mass communication, visual arts or related subjects. Other subjects include literature, sociology, psychology, journalism, management, business administration, advertising, sales, marketing, public relations, economics, etc.
Fashion designing require you should have knowledge of technical aspects, trends, and industry; apply creative skills; practice and develop a good portfolio. So, it is better to get a degree/diploma first. Designers initially work as intern, experience designing process and learn how the industry works.
[Answered on June 4, 2014]