People haven't been voting in enough numbers for long enough for the Church to have much to say about it. There's some motherhood and apple pie in the Catechism about voting being morally obligatory, and pronouncements of varying degrees of authority have been made about specific elections or specific issues, but as far as I know there is no developed, authoritative Catholic teaching on voting as a moral act.
Consequently, Catholics have a lot of different ways of looking at it.
One view is to vote for the best person for the office. Accordingly, I would vote for the same person I'd name if someone asked me, "Who do you want to serve the term?" Setting aside the question of how to determine who is "best," this is a very simple scheme that regards voting as equivalent to giving one's opinion.
Another view adopts a risk management approach when a viable candidate is judged to pose a risk to the common good. On this view, one would vote for another candidate to prevent the bad candidate's election.
A third view treats a vote as, in some circumstances, symbolic. One holding this view might vote for a candidate who symbolizes a certain idea or issue, despite believing the candidate would be a disaster as an office holder.
These views aren't exclusive. A person could use each of them on three different races on the same ballot without being inconsistent in his overall views on voting. But given a particular set of circumstances, is there any single view that represents "best Catholic practices"?