I dont know.. I was in the same situation 3 years back.. didnt have a team, no local or family connections..
But I loved the game, so just started watching..
And gradually due to a whole hoast of reasons, started to like and dislike teams..
Arsenal caught my eye due to their match against barca back a few years ago, where they came from behind to win.. I was watching it with some arsenal friends, and it was just quite something.. Then since, watching them struggle, loose players, have awful injury luck, get slated by everyone else.. yet still fight back and maintain a CL place, has endeared me to them quite a lot
United, I liked for SAF, who is just quite something... and a number of their individual players I liked
Park, hernandez, de gea, scholes etc. - and watching a team win is always nice (if we are honest)
Swansea, because a partner of mine used to follow them, and they were the team I rooted for in the championship season where they got promoted.. Since its just been great
Brighton, because of one match I wated a year or two ago, with them against liverpool.. and since then have had a soft-spot
And could keep going..
Then there are teams I dislike..
City+chelsea I dont really like, due to the constant changes in players and staff.. and the money aspects (though chelsea did grow on me, when watching them as under-dogs in the CL 2 seasons back.. not because they won, just because who can resist an under-dog story, and the drogba ending..)
I disliked spurs because of redknap..
I disliked liverpool because the people I know who supported them were dicks.. (awful reason, but still..)
And so on...
-- my point is, as a 'neutral' it doesnt have to be boring, and slowly over time you can just like/dislike teams, - and as you grow and become more connected with certian teams, maybe one day you will consider yourself a proper supporter
It seems fake to me, to just say 'I Support X, because of.. well I jsut chose'
Instead watch the game, join in the discussions, see what teams you connect with, and maybe in a number of years you would have deveoped a connection with a team, and become a supporter/fan/follower
-- seems a much more organic way of doing it, then just choosing
(all presumes you dont have a local team/family team)