1) join your local party. Typically they have county parties. Depending on the size of the city where you live in there may be a neighborhood group.
2) vote in every election.
3) if you have a specific seat in mind start attending their meetings regularly.
4) do you live in an area that has a neighborhood association? If so, join it and get on those committees. If there isn't one, start one.
5) find someone running for office in 2014 that you like. Volunteer on their campaign. That means phone banking walking precincts attending fundraisers etc.
This is a 2 to 4 year plan that will help you establish local credentials and give you an idea of what you are up againsnt