OTB Game

I played this game recently.  On the one hand, it illustrates a fairly common occurence in club level chess - my opponent got into time trouble and blundered approaching the time control through rushing his moves.  The main reason for posting it is a strategic question.  My opponent delayed castling, at one point I even thought he wasn't going to castle at all.  However, the standard (?) approach from my side of the board didn't seem to work i.e. sacrifice material to break through after building up pressure on the centre.  This was because as soon as I sacrificed, he would still have time to castle and I would just be material down.  He also had vague kingside threats.  I would appreciate comments from anyone who has experience of this type of thing.  It's a Sicilian with white (me) playing Nc3 and f4: