carroll is useless unless your going to play a very direct style
I personally use Carroll as my back up striker for Suarez. He's not very useful though, so I only really play/bring him on if I have a comfortable lead or for an easy game against a lower league team.
Although if you really want to play him I would recommend playing a very direct style and getting Charlie Adam to aim for the far post and place Andy there from corners. Although in my past experience he hasn't scored a single header in 20+ corners. Also set your full-backs to cross often.
Hope that helps
P.S I'm planning to sell him in the January transfer window by the way