Like Charlie and Vincent mentioned, being self-motivated to spend the necessary time is an absolute requisite to learning Mandarin. I found having 1-on-1 classes with a qualified teacher to be very helpful in the beginning of the learning process. A good teacher will help you form good habits and gets you on the right track to be more adept at studying/learning on my own.
Have you learned a foreign language before? Different people have different success with different methods. Just take the advice you get from this forum, Charlie’s other articles, and from wherever else you get advise and try all of it. Once you figure out what mode of studying gets you speaking/understanding effectively, maintains your motivation/interest to keep at it, and affords you the support of actually feeling like you’re making good progress then focus on that. I had a language teacher who gave sage advise: “lo mejor lugar aprender un idioma es en la cama.” His point was to thoroughly live the language and find the motivation to do so.