Help Can not Think of Nickname

All my friends in the net have awesome nicknames. Well, maybe not all of them but many of them have thought of some masterpieces. I want also to have a nice nickname. The nickname is like the clothes you wearing in real life. People great you and appreciate you in the virtual space if you have a cool nick. I am always wondering how people choose the name. I am trying for over a month, I am going to bed with the thought of cool nick but nothing happens. All the ideas I have had already be taken by someone. How long this will take?