The argument for a balanced parliament is overwhelming. Therefore, where labour are second and the Tories are first, vote labour. Where The Liberal Democrats are second and the Tories are first, vote Liberal Democrats. Simple!
Organise your friends and allies to help do this as it is very important to make sure the Tories do not have majority.
4/6 is generally available for a hung parliament with no overall majority. This is a very solid bet and i will be very surprised if any party has an overall majority. However Labour only have to get their vote out and be in 3% of the Conservative overall percentage to be the party with the most seats and this is because it generally takes 15,000 vote to get a Labour MP and it takes 20,000 to get a Conservative MP.
With the polls tightening is makes sense to take a gamble that the Nick Clegg factor will get out the left wing Liberal vote to stop a Tory majority and therefore give Nick Clegg the kingmaker role and a new voting system a chance of getting on the statute book.