Germany is part of the Schengen Agreement, which allows visa-free entry to citizens of the U.S. and certain other countries. All you need is a valid passport. If you are going to be working or studying in Germany, you do not need to apply for a residential permit until after you are in the country. You have 90 days upon entry to file your application.
If you have established that you do need a visa to enter Germany, you should apply at the German embassy or the consulate that has jurisdiction over your area. Use the consulate finder tool on the German U.S. Mission website listed below in Resources.
Complete and print the application form available on the website of the German Mission. Find it under "Visas and Passports" in the lefthand column of the directory of services. You must complete the form in either German or English. When you have completed the form, print it and take it with you to your visa application interview.
Gather the supplemental documentation needed for the visa. Along with the completed application form, you must take with you to the interview a printed and signed declaration (found in the same location as the application;) two passport photographs; a valid passport, and your original resident alien card or residency visa, plus a copy; previous bank statements, plus a copy, for proof of financial stability; insurance confirmation letter stating emergency medical coverage while abroad, plus a copy; a letter of reference from your employer; proof of airline ticket and hotel reservation, plus a copy.
At the time of your application you will be required to submit a visa application fee of $92.00. This must be paid in cash or money order written to the German Consulate General. Credit cards and personal checks are not accepted. Most German consulates do not require you to have an appointment to submit your application. You must check your respective consulate for information regarding the need for appointment. Visa turn-around time from submission of application is usually 10 business days.