If you're wanting to learn German and wish to visit Germany for practice, I do not recommend that you go to big cities like Frankfurt or Berlin. Everyone is used to speaking English in the bigger cities in Germany. Once they sense the slightest level of discomfort on your part about speaking German, they will switch to English. The result is that you may not be able to practice much German there. So try and get out to the country by taking the train or the tram and then, say, eating a meal in a German restaurant. Your efforts will be greatly rewarded I think. Here I am in a mountain restaurant above Zermatt asking my server where he thinks I'm from. What fun!