try to watch barca vs getafe game where barca lost 1-0 to them. its like they play 4-3-2-1 with roaming AM where they fill the midfield so that its packed. barca find it real hard to penetrate at the centre cause too many blocked pass.

i think another way to beat tiki taka is to counter attack and have a very good winger and avoid attacking at the centre as their full backs (alves and abidal) always go very high up.
i noticed that whenver pedro or villa gets the ball at the corner they never cross. they will try to beat the opponent or pass back as barca dont have a target man.
barca also might have some difficulties on narrower pitch because of their play. they should play better when they are at home.