It is prudent to start well in advance, as the procedure is a long one. A student should also enroll into a German language program as soon as he decides to pursue higher education in Germany. The doors of a university are open to a student only after he proves that he's entitled to be admitted to an institution of higher education. This is good for those whose educational qualifications or certificates are recognized as equivalent to those in Germany. If this is not the case, the student must undergo an eligibility test. In this case, each Federal State lays down the decisive criteria for evaluation of foreign qualifications required for admission. The preparatory institutions attached to the institutions of higher education are responsible for preparing students to take the eligibility test. 

An important aspect of admission: There are some subjects for which admissions restrictions apply throughout Germany. (Numerus clausus---NC subjects). For admission to one of these subjects students who come from countries belonging to the European Union can apply directly at the Central Admissions Office ZVS).
Zentralstelle fur die Vergabe von Studienplatzen (ZVS)
Sonnenstr. 171
D-44137 Dortmund, Germany
E-mail: poststelle@zvs.nrw.de 
Students belonging to other countries must apply first to the Akademisches Auslandsamt. 

Requesting Application Materials
Applications for admission and recognition of foreign certificates should be addressed to the Akademisches Auslandsamt (Foreign student service) of the institution at least 1 year in advance. If the student’s existing qualifications are considered to be non-equivalent to the German ones, he is expected to take a preparatory course from a Studienkolleg and also has to give an exam (Feststellungsprufung).


Where to Send Your Inquiry
Inquiries should be directed to the International Students Office (Akademisches  Auslandsamt) of the relevant institution.

What to Include
     Application Form
A completed application form should be sent. Most universities have their respective forms on their websites, which have to be downloaded, printed and filled out. If not, then you have to get in touch with the Akademisches Auslandsamt and ask them to send you the form and other relevant application material. The forms of many universities may be in German, although some provide forms in English for international students.
The following documents should be enclosed along with the application: 

• A certified copy of the certificate for admission to higher education or in other words the foreign high school qualification 

• A translation (from an official translator) of the high school certificate. 

• A passport-size photograph 

• Bio-data with exact information about one's education (schools visited, exams taken etc) 

• Proof of higher studies attended till now if applicable 

• Language certificate as proof of required German language knowledge 

• An officially certified photocopy of the assessment test to determine the eligibility of foreign applicants to studies at institutions of higher education in Germany with subjects and mark list, if the test has been taken.

Application Fee
There is no application fee!

Academic Credentials
Certified copies of your academic transcripts and degree certificates. If the certificates are in a language other than English, German, or French, you are expected to send official English or German translations of the certificates.

Personal Statement or Statement of Purpose
Most universities may ask you to send an essay or personal statement. This should include the reasons for you wishing to pursue a particular course in Germany, and specifically in that particular university. Your essay is assessed not only for its content but also for your clarity of thought, your language bility, your goals, and other relevant things.

Recommendations
Recommendations are expected to be from your professors, lecturers or employers. A lot of weightage is given to the letters of recommendations in making the admission decision. Some universities send their own recommendation forms with ratings, while others may expect them on official letterheads. The recommendation letters have to be sealed and the person recommending you should sign on the cover.

Deadlines and Submission
German universities are very particular about deadlines. Any application reaching late is not processed, no matter how impressive. The deadlines are as follows:
Winter Semester (October)---July 15th
Summer Semester (April)---January 15th 
In case you need to send your applications for central assessment first, then the deadlines are as follows:
Winter Semester (October)---May 15th
Summer Semester (April)---November 15th
After your qualifications are cleared, you have to then apply to the respective universities before the above-mentioned deadlines.

Preparatory Studies for Foreign Students

Applicants whose certificates aren't recognized still have a chance to study in Germany. They can enroll at a College of Preparatory Studies for Foreign Students (Studienkolleg). Enrollment for the preparatory courses is handled by the university. As with every other authority in Germany, one needs to apply in writing. The Foreign Students' Office (Akademisches Auslandsamt) at the various universities will provide you with more details. 
The preparatory program lasts for one year at the end of which foreign students have to take a final examination. If they pass the exam they are considered to be up to the academic level they need to study at a German university and can apply for admission. 
The preparatory courses are conducted in German, so language proficiency is a must. 
The German language diploma of the Culture Ministers, Level 1 ("Deutsches Sprachdiplom") as well as the GoetheInstitute's "Zentrale Mittelstufenprüfung" are considered proof of your language fluency.