When I attended the Polyglot Conference in October of 2015, I met Benny Lewis, author of the book Fluent in 3 Months.  I bought his book and found that there was a lot of helpful information in it, regardless of whether you are dedicated enough to learn a language in a short period of time or are looking to learn in a more relaxed time period.  I would emphatically recommend reading his book, but here is his website which is also a great resource for hacks, tips and tricks for making language learning more enjoyable and less frustrating.  

A little about Benny: He was not a successful language learner in High School and even dropped out of his Spanish class.  He spoke only English until the age of 21, but now speaks more than a dozen languages.