To be a successful (or an improving) photographer, your subject matter has to be accessible. If you're in NYC, then street photography is a good idea. Live in a one traffic light town in Alabama (sorry about the US centric examples) where you see a pedestrian once every 15 minutes, then street photography is not a good idea. Same with landscape photography. If your lifestyle precludes you from long stretches of driving (or flying) to get to locations, then that's probably not the right subject matter for you.
That being said, before you get too depressed with my advice, look up Michael Kenna. Most of his photography was done in a specific locale (i.e. not too much travel) and several of his books pick pretty ordinary landscape or urbanscape subjects. Yet he creates masterful b&w work.
Without seeing this "very boring part of Germany" that you live in, I'm fairly certain that you can make amazing pictures. It just won't be the traditional, cliche, color landscape photography that is all over insta. You'll have to figure out a style that works for your geographic location.
Zillions. However, start her: http://www.amazon.com/Michael-Kenna-20-Year-Retrospective/dp/1590050193/ref=sr_1_3?ie=UTF8&qid=1448462990&sr=8-3&keywords=michael+kenna
Michael Kenna is the master of composition. That makes this the most beautiful text book in the world.