Decide what goods a retail store will sell, and how they will be marketed.
As a Fashion Publicist you are the Public Relations Representative for your client. This means you promote, exalt, and proclaim how wonderful their product is in an attempt to convince Editors and Journalists to notice it. Like all good PR Reps a Fashion Publicist also does damage control, so when your Fashion Designer knocks out a camera man with a chair you are there to send flowers to appropriate parties and smooth talk the press into ignoring the rumors about a broken nose.
Being a Fashion Publicist is a great position if you want to be at the intersection of media and fashion. You get to work very closely with a brand or Fashion Designer and spin their stories in a way that is both true to their style and favorable to their public appeal. To do this you must think up ways to continually get your name in the press, go on talk shows, write press reports, and generally garner as much attention as possible. Ideally you would love this attention to be positive, but if its not then you need to make it less negative.
So you are a mix between a Politician, News Correspondent, and a fashion connoisseur. You must be on your toes at all points and react appropriately to whatever situation comes your way whether you are on a radio show or at an opening gala.