An instant-runoff balloting system should be adopted so voters can list their candidates in their order of preference. This will permit voters to rank their choices as they truly see them without losing their vote if their first choice doesn't receive enough total votes.
Preferential balloting is used in Australia, Canada, UK and in some jurisdictions domestically. It's simple, easy to recount, and gives the voter the opportunity to put a third-party candidate first without fear of "throwing away" their vote.
The following Wikipedia article is quite in-depth with examples, history and where it is used:
http://en.wikipedia.org/wiki/Instant_Runoff_Voting