The way most people do it I guess, is (assuming you're an American):
Start watching matches with American players involved. In the PL, Howard at Everton would be a good shout, or Dempsey at a club like the Sounders. From there, you might find yourself following that team more.
Or Arsenal might beat Everton 6-0 one day and you'll think "fuck that team was awesome to watch, gonna watch them more", so you decide to do that.
I think an easy way for a lot of new fans to join in is to watch the Champions League, because even without affiliations it's fun to see the big guns go at each other.