To master and excel means you already speak german and know the basics and you are looking forward to fluency in speech ? If so then reading ,listening and speaking will help you on the long run. Reading adds up to your vocabulary ,your ability to use more expressions and refines your sentence structure ,since it is a bit complicated in german specifically . Speaking and praticing the language with natives or ones who speak it well ,helps you a lot to pick up words also and to speak fluently . Lots of listening to music , audios , watching videos all together help too. If you do all that then it is a matter of time to reach a certain degree of fluency :)