It's difficult to make a social network better than Facebook, it's too big to kill being just better in something, they can just fix it or buy you and continue with the monopoly.
There's lots of users that don't like Facebook anymore because it's full of crap and you are friends with people you just know but you have no interest on their life.
If you check the other social networks that compete in some way with Facebook they are all different and they focus in another approach to users.
More than being better I would try to be different and find this new market that can start small and bring more and more people together and making these connections useful for everyone.