Looking for a Furnished Room for Long Term

I am 28, from Turkey and a graduate student majoring in International Economics and Business. I have lived in a flatshare for 6 years as the primary tenant and had flatmates of different nationals and gender, so I am used to living in a shared house. I am very enthusiastic about learning German, therefore, I would like to communicate in German (well, let's say most of the time :) ). I am tidy and organized. I don't have very specific expectations about the house (price, location, room size, etc), just reasonable conditions are enough. Of course, I do not prefer very crowded houses, very far places, rooms that do not receive much sunlight. I quit smoking a year ago, but, it is ok if you are smoking.