4. Create time and space for the language
Learning a language is like learning an instrument. If you have a lesson once a week, then you go home and forget all about it and only remember it once the next lesson arrives, it is hard to really learn playing the instrument. It's the same way with learning languages. It is important, to create time to learn. Time, where you can work at learning this language from home. This doesn't mean you'll have to learn each day all day; it means, take some time to repeat what you've learned and therefore steady it. I am talking about 10 minutes a day. That is why there is homework: it is not for controlling you, but a poissibility for you to take the language home.
It is also very important to create space for the language. I have known many students who never used the language at home or at work., because nowadays you'll do just fine with only speaking english. But id you don't have the possibiliyt to speak german, your motivation decreases and the success will not occur.