What is the best way to find a job in UAE? online application through job sites? head hunters? job fairs in UAE? or something else?

The best way to find a job is to do all of the things you mentioned on a routine basis.  I keep logs of who I have applied to and what position.  This helps me keep track of how many jobs I have applied for daily.  I set a high goal, such as, everyday I make contact with at least ten companies and spend at least30 minutes networking.  This keeps me focused and increases my chances of finding the job I want.