I have heard people tell me that it's difficult to maintain their language skills because they say they don't live in an area with a lot of Spanish speakers. To a certain extent, I agree, but my contention is that it's not the numbers that count but rather how you make the most of them. Even if you live in an area with a large number of bilinguals, how and how often you interact with them might depend on your skills, and willingness to use them. In addition, if you haven't developed basic fluency yet, bilinguals are often not the best choice for speaking partners since on average, they are more likely to switch to English rather than patiently wait for you to finish your thought in Spanish. If you live in an area without an obvious Spanish speaking population, they still may be around but you'd have to seek out the community. For listening and reading there is no limit to how much you can access especially with the Internet. Satelite TV providers have Spanish language packages with numerous channels from around the world. There are also language exchange sites that have real time voice chats like sharedtalk and livemocha. But there's nothing like interacting face to face with people in person. I feel that networking is the best way to grow your circle of contacts. You may have friends that speak Spanish (even if they use English with you), and they have family and friends. Hopefully you get invited to their get-togethers and get to meet others and so on. If you belong to a church, they may have Spanish language services, which could be good listening practice or a way to meet other people.
The important thing is to have daily contact with the language no matter what form that may take. In the U.S., where English is the dominant language, you can never get enough listening and speaking practice in Spanish, so dive in and soak up as much as you can!