While Twitter and LinkedIn are great tools for networking, they should never be a substitute for face to face contact with another human being. Rather than putting all your efforts into maximizing your online persona, it’s a good idea to put just as much (if not more) effort into working the room a little more.
One great thing about networking in person is the rapport you will build with the person you’re talking to. Meeting someone face to face is likely to showcase who you really are, and makes you a far more likeable candidate than someone they’ve only ever conversed with online.