Take ballroom dancing lessons. Find them in the phone book or online. Learn all the ballroom standards: the waltz, cha-cha, rumba, tango and more.
Find a partner, and continue practicing ballroom dancing until you are both very accomplished.
Register with USA Dance and join a USA Dance Chapter in your area. These can be found through the USA Dance site.
Compete in USA Dance recognized competitions. Work your way up to the more advanced competitions, placing high or winning each one. As you and your partner win, you both will gain more and more attention.
Make appearances without your partner as you both become more noticed. Create a buzz, and make it known you wish to dance on "Dancing with the Stars."
Continue winning competitions, and compete around the world with your partner.
Go to every audition for "Dancing with the Stars." With all of the work you have done with the competitions and publicity for yourself, you should stand out, thus making yourself a shoo-in for the show.