Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Brilliant!

This is possibly the most helpful self-teaching book I've ever seen. If you stick with it and do all the exercises, you'll be shocked at how quickly and how well you learn the language. Keep in mind that you will still need to either take classes with a live teacher or get an audio teaching course on top of using this book, or your pronunciation will probably be terrible. I also got some vocabulary flashcards (and make my own for the alphabet), but whether or not you'd find those helpful just depends on how you learn best.