I am training to be an ESL teacher, so the best way to acquire a new language is through vocab drills, followed by studying the syntactical structures of the language. Once you start with those you can use authentic second-language material such as newspapers, menus, television, movies to practice and get a feel for the language. As mentioned previously, finding a native speaker of the language you wish to study is a great way to learn, and if you have the resources, immersion by way of travel is the best. I am currently learning cantonese from my girlfriend and her family. Learning a new language is can be really tough but also rewarding. Best of luck.