Preparing documents for a student visa to study in Germany typically involves gathering several essential documents. Here's a general list, but keep in mind that specific requirements can vary based on your nationality and the German consulate you apply through:

1. Valid Passport: Must be valid for at least six months beyond your period of stay in Germany.

2. Visa Application Form: Completed and signed. You can usually download this from the website of the German embassy or consulate in your country.

3. Letter of Admission: From the German university confirming your acceptance and detailing your course of study.

4. Proof of Financial Resources: To demonstrate that you can support yourself financially during your stay in Germany. This can include bank statements, scholarship award letters, or a letter of financial guarantee from a sponsor.

5. Health Insurance: Proof of health insurance coverage valid in Germany. This could be either from a German insurance provider or an international health insurance plan that meets German requirements.

6. Proof of Language Proficiency: Depending on your course requirements, you may need to demonstrate proficiency in German or English (depending on the language of instruction).

7. Biometric Passport Photos: Usually, two recent passport-size photos that meet specific requirements (check with your consulate).

8. Proof of Accommodation: Confirmation of where you will be staying in Germany, such as a rental agreement or a letter from the university.

9. Educational Certificates: Copies of your academic transcripts, diplomas, and any other relevant educational certificates.

10. Cover Letter: Explaining the purpose of your visit, your intended course of study, and how you plan to support yourself during your studies.

11. Proof of Payment: Receipt showing you have paid the visa application fee.

12. Health Certificate: Sometimes required, indicating you are in good health and free from contagious diseases.

Always check the specific requirements on the website of the German embassy or consulate in your country, as these can vary and may include additional documents or steps.