Remember how that player had been playing during the rest of the tourny
If you can see a flop for not much more than the blinds, then see it. In heads up, any 2 cards can win.
If you have decent cards and the BB, raise it when other player limps in, make them make a decision to risk their chips.
Be prepared to be put all in or fold at any time, so if you raise, and get reraised, be willing to let it go or take um out.
You dont have to protect the BB with 72 offsuit when the other player goes all in!!
Just a few tips, but I am sure you have seen them all before.