Maybe your work could suggest a course for you to take.  Otherwise if they are not specific in what you may or may not do --- what is the point.  They have to criticize you for something because apparently there are no perfect employees.  

True that some people get promoted because they are liked not because of competence.  Usually they are taking credit for others work too.  You might just have to smile sometimes, walk around and say hello to people and ask then how they are.