It is not enough to be registered, you need to know how you are going to get to the polls. What time do the polls close in your area and when do you anticipate there will be the most traffic going to the polls. The polls open at 6:00 am in Missouri, I plan to arrive at 6:05 am to vote. To find out when your polls close look at the political wire as they have them listed out by times and state.
In addition to deciding the most appropriate time for you to vote, you may also offer to go with a family member or coworker. My wife and I plan to go before work. Going with someone to the polls makes the process all the more enjoyable, especially if there are long lines.
If your state allows it, you should also consider voting early. That is, you may already be able to vote and thus avoid any lines that will occur on the 4th.
Here is a list of closing times in your local time. So if you are in Missouri and it says 7pm, then that means your polls close at 7pm CST. I am going off of the list on Political Wire, sorry if my math is off at all.
6:00 pm - Indiana (East), Kentucky (East), Arizona
7:00 pm - Illinois, Kansas, Kentucky (West), Florida, Indiana (West), Vermont, Georgia, New Hampshire, Virginia, South Carolina, Missouri, Mississippi, Oklahoma, South Dakota, Tennessee, Texas, Colorado, New Mexico, Wyoming, Utah, Nevada, Oregon(East)
7:30 pm - North Carolina, Ohio, West Virginia, Arkansas
8:00 pm - Alabama, Connecticut, Delaware, Florida (Panhandle), Massachusetts, Maine, Michigan, Maryland, New Jersey, New Hampshire, Pennsylvania, Minnesota, Nebraska, Texas, Wisconsin, Idaho, South Dakota, California, Oregon(West), Washington, Montana, Alaska
9:00 pm - Louisiana, New York, Rhode Island, Iowa, North Dakota