If I was to participate in a election using the [Single Transferable Vote][1] system, what would be my best strategy to try and prevent one candidate from winning.

For example if there are 5 candidates. One who I would like to win and one I very much would like not to win (and 3 who I don't have much opinion either way one).

It is however most important to me that the one I dislike does not get in (I disagree strongly with their policies etc) 

What would be my best strategy?

 - Vote for all with Mr/Ms bad policy in last place?
 - Vote for all Except Mr/Ms bad policy in last place?
 - Vote for just my top 1,2, or 3?
 - Something else?

Is there a difference if there is only one seat, or several seats?


  [1]: http://en.wikipedia.org/wiki/Single_transferable_vote