Once you know who your supporters are, you can make sure they vote. And in the case of voters who don't support you, there's a strategy you can use on them too.

Greek voters angry about the prospect of more crippling austerity measures gave scattershot support on Sunday to a range of anti-bailout groups, likely extinguishing chances that either of the two once-dominant parties would form a government.

Armed with the endorsement of former rival John McCain, Republican presidential candidate Mitt Romney is seeking to lock down support in New Hampshire while preparing to woo voters in the conservative bellwether of South Carolina.