The German language can be a complex language to learn by someone who has been speaking English (or other languages) for over a decade or more. But thinking from this perspective is where the trouble starts. Expect to have further difficulty on other levels of the German grammar and language itself, as a whole if you have this kind of learning attitude.

But really, the only way you'd be able to learn properly and fast other languages than your own is by accepting that you have to go through stages of learning before you become a master. Part of this process also requires for your mental ability to retain information, especially new ones. Since the words are foreign, expect to hear strange words you've never heard before. Familiarity is one of the things which make it harder to remember and in learning German (or other languages), memorization is crucial.

The German language matters in three aspects. First are you grammar, followed by your pronunciation and third by how you use it in actual situations. What you really don't want to do (similar to what everybody else avoids) is to make a mistake when you get out there and practice your German speaking skills to a native German speaker, right? That's where you're wrong. The problem is that we expect too much from what ourselves is capable of doing that we end up without gaining anything. In learning a new language, always stick to the open-minded rule because you'll never be perfect on anything unless you made mistakes.

For those who just can't seem to let go of their English language, spending your time getting to know a German native speaker would be the next best thing to do to let go of your English language for the meantime. It works two ways actually. One is you are forced to speak the language you are trying to learn and two, when you're confused of something, you can ask for help right away.