Ideas for marketing and selling: Use Facebook. It's an extremely powerful tool for selling work. You can post pictures of your work with a price and all of your friends will see it, they might even share it. You can even start an auction and let people bid by using comments. Otherwise you could use another site like Etsy to sell work, even Ebay or Craigslist. With the internet, you can get a pretty good audience no matter where you are. Marketing is easy with the internet.
Otherwise you could try local galleries. Bring a portfolio, show them your work, and see if you can get them to let you display there. You could sell work that way too. If you get in on a big show at a gallery you can advertise your work with posters. You can even find galleries at the mall, that could be another place to look.
Also, as far as marketing goes, you gotta pick your audience. Try to sell to people you think would buy your work. Friends and relatives are an easy start, but you can also target people with a specific interest in what you do. For example, you are making 3-D castles. Kids at the hobby/game shops would love that. Play to your audience.
Does that help?