Which is one effective strategy used by the polical campaigns?

One effective strategy used by the political campaigns is the door to door strategy.

This strategy is used mainly in areas with a large number of undecided voters in a local election.This is a very personal form of voters contact as it is literally a face-to-face meeting. It is also the cheapest of all the strategies, all a candidate has to invest here is some of his time and the cost of printing some leaflets that he leaves at the voters' homes. The candidate himself should canvass the areas with the most of undecided or swing voters and his supporters and volunteers could cover the rest of the district. The goal of this strategy is to get to talk as a many people as possible and to convince them to vote for a particular candidate.