Most people have studied a foreign language at some point in their lives. For most people, their first foreign language experience was in a classroom. For many, this was also their experience. After a year or two of study, the average learner will give up in frustration and / or boredom. They assume that they just do not have a talent for languages. Unfortunately, this does not have to be the case. These people just are not using the right techniques. There are many more more direct methods for learning a language.
The main drawback of a foreign language school is that it is not geared specifically to your needs. As adult language learners, we learn best when the information is specifically geared towards our immediate needs and interested. A foreign language school, on the other hand, will have a set curriculum designed for a much more generic audience. The classes themselves will usually proceed at the rate of the slowest learner. For each student, there also will be a lot of down time while the instructor spends time with other students.
The most successful learners often take a much more independent approach to learning a language. They use methods that put them in charge. They decide what they need to learn and how they are going to learn it.
The first step is to get a basic feel for the structure of the language and to learn some basic survival vocabulary. One of my favorite methods is to use a purely audio program such as the Pimsleur languge program. Using this method, you'll gain confidence in the basics fairly quickly. I like to put them on my Ipod and listen to them while I am stuck in traffic on the way to work. I'll usually arrive at the office with an uncontrollable urge to greet the first several people I meet in the foreign language.
After you get the bare essentials of a language, the next step is to switch gears and take a much more self directed approach.
One powerful technique is to immerse yourself in a language. You can do this easily by quitting your job, moving to another country and living in a small remote village for a few years. In order to survive, you'll be forced to learn the language.
Or, if you are not quite ready for such a drastic step, it is possible to immerse yourself in a language without ever leaving home. There are several options available to you. I recommend taking advantage of all of them. Watch movies in your target language, read magazines, listen to the radio or podcasts, and most importantly, find a native speaker to work with. But in all cases, immerse yourself in real life examples of the language.
Surround yourself with your target language. Spend your time listening, watching, reading, and speaking in the language as much as possible and you will make progress in the language faster than any student in a classroom.