First, I will vote solely on the basis of three issues:
1) Restoring legal protection for all human lives.
2) Preserving the unique legal standing of permanent, heterosexual monogamy, in recognition of the institution of marriage as the basis of civilization.
3) Reversing the trend towards judicial tyranny, and restoring constitutional checks and balances. This is an issue because of items 1 & 2. Namely, the legalization of abortion and of same-sex 'marriage' was thrust upon us mostly by judicial fiat, and not via the democratic process. This simply must be rectified; judicial oligarchy must not be allowed to take over completely.
These things are fundamental. When/if they ever become resolved satisfactorily, I may consider other, lesser political issues, but not until then.
Second, I will not cast my vote based upon which candidates are doing well in the polls or in other states. I ignore polls. Here's why:
1) Consider two hypothetical candidates A and B, with roughly equivalent policy positions, but with one difference: Candidate A is known to vacillate according to popular opinion polls, while candidate B is more solid in his positions, even when they become unpopular. In such a hypothetical case, I would prefer candidate B, as more principled and reliable. I think most voters would concur. We voters ought also to do likewise, voting on principle without watching poll numbers.
2) Watching the polls, and voting only for an electable candidate is circular reasoning.
3) Don't tell me I'm wasting my vote. Besides being circular reasoning, voting based upon how others vote is to be, by definition, a trend follower; it is to allow other voters to dictate your vote. I'd rather be a trend setter.
4) God is watching.