One might consider the hopelessness of trying to run an ideology against an incumbant. The incumbant will win pretty much every time.
One might generalize this to: "The easiest way to beat an opponent is to run a better candidate." Note, a better candidate does not guarantee a victory, but it makes it a whole lot easier.
Without knowing the candidates or the locality, various factors in any election include: popular (local) politics, party, party support, funding, charisma, demographics, and platform, to name a few. Simple possession of "conservative" credentials is preferred, IMO, but hardly provides sufficient groundswell to automatically beat out all other factors. Better ideas, persuasiveness, effectiveness are usually useful, too.
Continuing the theme of "Where to begin..."
The beginning. How do you get the best candidate into the race? Support him from the beginning of his career. Sitting out an election is dumb in the extreme when you consider that the guy running for dogcatcher or the gal that wants a school board seat is going to be a congressional candidate ten or twenty years from now. Put the best people into government at ALL levels and the cream will be able to rise to the top.
If you feel you must punish a candidate, just don't vote that race. Why would you throw away good choices in the future just to let everyone know todays choices $uck?