I've always been of the opinion that if you don't vote you give up your right to complain about what elected leaders do. The argument that one person can't change anything doesn't hold water because a bunch of "one persons" can change an election.
But what if you don't believe either candidate should be in office? I've always held my nose and voted for the lesser of two evils. The problem with that is, the lesser of two evils is still evil and I'm not going to do it anymore.
So do you stay home and not vote at all? That's where I think you lose your right to complain. Usually there are enough races on the ballot to vote for the ones you believe in and leave the rest blank. I don't know about other states but Oklahoma does allow undervoting.
Show up, sign in, and vote for the candidates you believe in. Leave a particular race blank if you don't believe in either one. Don't vote for a third party nobody just to avoid candidate A and B. If 20% of the voters turn in their ballots with no vote for president, regardless of who wins both parties will start wondering what you're looking for. In four years you might just get it.