Vote even if the media insist your candidate doesn't have a chance. Your candidate doesn't, if all his/her supporters stay home.
Vote even if it's inconvenient--even if it's difficult--even if there's a line out the door of the polling location and you hate standing in line.
Vote even if no candidate passes your personal purity test by agreeing with you on every single point. Vote for the best you can find--or against the worst if you must--but vote.
(I was going to post this late last night, but a line of thunderstorms came through and blipped our power.)