Check with your state to see if your voter registration is active at your current address, and you know where to go to vote. Don't know how? Use these search terms to find out: am I registered to vote and include your state. Live in California? Try am I registered to vote California.
All of your friends can do the same, or they can register in person locally, and get their voter registration card. Also, in states that require photo IDs, help those people who don't have them to get the ID in time for the primary and general elections. Many local libraries have computers where those who don't have their own can use the Internet. When I go to the library in the morning, most computers are being used by my Amish neighbors!
Rock the Vote and many more organizations around the country are helping with this effort. BUT if you give a registration card to someone who is soliciting registrations, be sure to double-check online or by phone to be sure that your registration is valid.
Get out and vote! Give friends a ride, too.