Here comes all the advice, usually from the right (you want to listen to the "enemy"?). Tim Noah makes some very good points:

The process of moving the Democrats rightward has no end point, because every time the Democrats shift rightward the Republicans respond by shifting a little further rightward so they can continue to denounce the Democratic position as radical leftism. That explains why the GOP of today is so much further right than the GOP of the Reagan era, when Republicans were still willing to support expansion of the earned income tax credit for low-income workers; more progressive taxation of Social Security benefits; arms control; and promotion of human rights abroad. (This rightward shift was documented compellingly by Joshua Green in "Reagan's Liberal Legacy" in the January/February 2001 Washington Monthly.) In theory, there ought to be a point where the GOP has moved so far to the right that nobody will vote for its candidates. But in practice, I'm not confident that such a point exists.