Ruy Lopez: Where Did I go wrong?

At move 11 look at knight to f5 instead of bishop to f5 the bishop is trapped because if it moves black loses the exchange. Then bringing the queen to f3 to try to get an exchange of queens on f3 ie queen takes on f3 then knight on f5 takes queen. The idea is that both blacks bishops and his queen are all set to stage an attack on your king side. So you try to exchange off the pieces to at least disrupt the attack.

First mistake and what lost you an important tempo in the opening is the fact that you first pulled the bischop back to a4 and then after the opponents next move captured the knight anyway. Why not capture right away and get an extra move or keep your bischop on the nice diagonal and develop another piece, your knight maybe?