I'm doing my part to help democracy tomorrow: I'll be at a polling place for over 12 hours. If I can do that, you can do your part: spend (hopefully) less than an hour to get to your precinct, stand in line for a bit, and make your choices known. If you haven't turned in your mail in ballot, get thee to thy County Clerk's office before 7 PM. If you're voting at a precinct, make sure you're in line by 7 PM. Everyone in line gets to vote, no matter how long it takes.
Do not wear a campaign shirt or button to vote (or bring an overshirt). Electioneering is outlawed within 100 feet of a polling place and you may be asked to cover your shirt.
If you have any legal problems voting (e.g., someone tries to prevent you, you're not on the list you're supposed to be on, etc.), see if there is a lawyer on site. Colorado's status as a swing state means many precincts will have a legally-trained poll watcher on hand. If no one present can help you, call 1-866-OUR-VOTE or 1-866-MY-VOTE-1.
Consider taking a cell phone or small digital camera to the polling place. If you have any issues with a touch screen system, video the vote
If you haven't made up your mind about ballot initiatives, review my post
from last week. In the end, I voted NO on 50 (gambling) and 51 (developmental disabilities) for several reasons including those discussed in the comments. I won't be upset if 51 passes, though.
Note: All specifics above apply to Colorado voters. Your state's rules may vary.