I listen to what they have to say and how well it aligns with my feelings on local items.
I will admit to having some build in prejudices. If a candidate wears their religion on his sleeve, I will NOT vote for them. If a candidate wraps themself up in the dressing of one particular party and expects me to vote for them JUST because they belong to that group, I will NOT vote for them. If a candidate wages an extremely negative campaign, not addressing the issues but attacking their opponents, I will NOT vote for them. If their entire campaign revolves around their position on issues (such as those on the national or state level) that they will NEVER have any say over or input into, they will NOT receive my support. If it is a school board position and you support either a voucher system, forced prayer in school or demand that Creationism, Intelligent Design, Divine Intervention or whatever be taught in conjunction with or in lieu of Evolution, they will NOT get my vote.
I also look at where they are from; what is, or was, their profession prior to running for this office. Lawyers, Realtors, Bankers have a hard time winning my vote. Past experience seems to indicate they are either beholding to, sympathize with, or are more likely to vote favorably for their particular group rather than their supposed constituents, usually to the detriment of the community.