Factors affecting success

• Leadership

  Voters respond to the quality of the leader.

  Voters prefer an experienced leader with good media presence.

  Leaders represent the party, if people don't like the leader its unlikely they'll like the party.
• Party Unity

  A disunited party has no hope of being elected.

  E.g new Labour was united around Blair, and so won a landslide. Whilst Major had been wracked by party division.
• The Media

  The electorate is often influenced by the media.

  Newspapers tend to line up predictably around elections.

  Newspapers only reinforce existing views and do not change minds, however some swing votes may be swayed.