From the NY Times:
1. Know where to go. In many states, you will not be allowed to vote if you show up at the wrong polling place. Worse still, you may be given a provisional ballot to vote on that will later be thrown out. Your board of elections can tell you where to vote. If you can't reach the board, a nonpartisan hotline, 1-866-OURVOTE, has a polling place locator. So does the Web site www.mypollingplace.com.
2. Bring proper ID. The rules vary by state. If you have a photo ID, it's wise to bring it, just in case. Too often, poll workers demand ID when it is not required, or demand the wrong ID. If you do not know the law in your jurisdiction, you should check your local board of elections Web site.
3. Review the sample ballot before voting. Ballots are often confusing, and their designs can change considerably from election to election. And as the infamous "butterfly ballot" showed in 2000, a poorly designed ballot can trick voters into choosing a candidate they did not intend. If you have questions about how to vote on your ballot, ask a poll worker or poll monitor for help.
4. Check your ballot before finalizing your vote. As we saw in 2000, if punch card chads are not punched out precisely, votes may not be counted. On electronic machines, a brush of the hand can erase or change a vote. On paper ballots, stray or incomplete marks can disqualify a vote.
5. Know your rights concerning provisional ballots. No voter can be turned away in any state this year without being allowed to vote. If there is a question about your eligibility, you must be allowed to vote on a provisional ballot, the validity of which will be determined later. But if you are entitled to vote on a regular ballot, you should insist on doing so, since a provisional ballot may be disqualified later on a technicality.
6. Know where to turn for help. If you experience problems voting, or if you see anything improper at the polls, you may want to get help. There will be nonpartisan poll monitors at many polling places. (There may also be partisan poll watchers, and it's possible one of them may be the person objecting to your voting.) It is a good idea to bring a cellphone, and phone numbers of nonpartisan hotlines like the Election Protection program's 1-866-OURVOTE and Common Cause's 1-866-MYVOTE1.
7. Be prepared for long lines. In some precincts, the wait may stretch into hours. Try to get to your polling place very early in the morning, or between the before-work and after-work rushes. As long as you are in line before the polls close, you are legally entitled to vote. Do not let poll workers close the polls until you have voted.