Today is Election Day, so go vote. If you live in Florida, and don't know your polling place, visit the Florida Division of Elections website, which can direct you to your county supervisor of elections and polling place locations.
Many people go into the booth and don't know what to vote for. Before you go, check out your local newspaper and television news websites. The more diverse the information sources are, the better off you will be. Nothing is wrong with leaving a blank (I know people who left the US Senate race blank), but better to make an educated "none of the above" vote, than a blank because you don't know the race.
In addition, vote the entire ballot. Several cities and counties have very important initiatives and referendums, which are listed at the end of the ballot. For example, Hillsborough County and Polk County are both considering building countywide transportation systems, including road and pedestrian access construction. (It is rumored if these pass, Pinellas County will ask the same ballot question in 2012.) Duval County is voting to change when their Mayor and City Council is elected from spring to fall. Each initiative is significant to the individual communities. But not voting or by not educating yourself on each issue, you're only hurting your community's future.