Student looking for accommodation in Berlin

The cheapest way to live in Germany and popular among students is a room in a shared apartment known as a Wohngemeinschaft or WG. It is important that people get along so similarity in ages, interests etc. can be important. Usually one will not be accepted unless the people already living there decide for you. Normally they want to meet the person themselves but in this day and age if one has not arrived in Germany then maybe an online chat of some sort can be arranged.

The way it is usually done is by people looking for a room, or offering one, put up notices on a message board at university. Maybe you have contact to someone in Berlin that could put up a notice for you? Otherwise, you might have to settle for temporary accommodation like a hotel or hostel and start looking after you arrive. This means uncertainty when, where and if you will find something but one can also better judge a place, the roommates and the neighborhood by seeing them with their own eyes. If one hasn't found something in advance then it really makes sense to show up a couple of weeks early if possible to look for a room before classes start.

@TominStuttgart thank you very much for the answer! I found it very helpful

From what I heard, Berln has one of the tightest housing markets in Germany. So don't expect the search to be easy or quick! So sooner you loosen your (rather rigid) criteria, the better.

Also, as Tom already hinted above, it will be much easier to find a place once you are in Germany. Most landlords and house-mates want to meet the candidates in person before they decide - so an applicant whoisn't here will usually be removed from the shortlist. And also you should have a look at the place, as there are any duds or even scams.

Additional sites to look at are kleinanzeigen.de and wg-gesucht.de. The are, of course, entirely in German, as are all tenancy contracts - so you should get a local friend's help to sort this out if you aren't fluent!