Bubble with Big Stack

[bluewilde]

All right, so most of the time I get to the elevated blind levels and have 600-900 in chips and start to steal because of the pressure I feel from the blinds. But more and more, I'm arriving with a more sizable stack, and don't seem to be doing a good job of judging when to steal. Hence I tend to be playing pots out and losing when shorties push and I don't wanna call with 2nd pair. Any advice on how to handle the big stack?