I took French for 3 semesters in high school. Yet I can barely say "hi" in it. Back then I took it just to fulfill the requirements.
I've decided to take Spanish101 next semester. Unlike when I was taking French, I genuinely want to learn Spanish and be able to communicate in it. I'd love to hear how you went about getting somewhat fluent in a foreign language.
Having studied a number of languages, I've come to believe that being forced to speak and write at the outer limit of your ability is the most effective way to learn a foreign language (listening and reading will come effortlessly as a side effect). However this is somewhat expensive, emotionally tiring (adults aren't used to the experience of constant failure and correction), and it can be hard to find someone who will really pounce on every mistake.
I've found intensive immersion programs with small classes to be a good second-best, especially at the beginner level where progress is very rapid and you have a chance to internalize proper phonetics and grammar.
A possibly useful image: you have about ten thousand wrong sentences you have to get out of you before you are speaking the language well, so you need to find someone who will help you get them out of your system as efficiently as possible.