In order to be qualified to teach English in Germany, you must be a native English speaker and hold certification in TEFL (Teaching English as a Foreign Language). If you have those two requirements under your belt, and you are aware that you'll be living in Germany for at least a year, you're ready to begin your job search.

According to those who have experience in teaching English, the best positions are offered in the small cities and towns.  If you're looking in a large metropolis, it's going to be more difficult to find schools that need your help- not to mention more expensive to live once you're hired. No matter what city you choose, the first thing to be done is to contact establishments you are applying to in person or by mail, and inquire about available jobs.

 On receiving the job offer, you should go straight forward to the registry office. They will be able to supply you with a three-month visa while the rest of the paperwork is organized. If you are USA of UK resident you need only residency permit to be able to work in Germany. In order to obtain this you will have to have proof of employment, health insurance, and proof of payment into a pension fund, as well as a German address. Try using 3 month visa to obtain these things, go back to registry office and take your legal work and residency permit.

Money matters
Teachers who work in Germany often get high salary wages, comparing to teachers of English in other European countries. You may expect the equivalent of around $20 US dollars an hour... however, be aware of the fact that taxes in Germany are sky-high, and your take-home pay won't be anywhere near this amount. You should do a kind of research to this matter and discuss wages with your future employer regarding on how much is really necessary to afford good living conditions. Too many English teachers in Germany are unprepared for the tax situation and end up taking a job that seems high-paying enough but isn't once the taxes cut it. 

You can also avoid the tax problem by becoming a full-time teacher. Many teachers come to Germany and choose the freelance job; thanks to it they pay no taxes. You may have an ongoing contract with a school, but unless they are willing to put you on the payroll as a full-time employee you will be subject to large taxes. But try to find the school or other organizations that will employ you full-timely, because here you are to earn quite substantial sum of money.

Germany is starved for English teachers, and if you have the right qualifications and a solid sense of adventure, teaching English in Germany can be a great experience. Having good geographical location, Germany is an attractive country for those who not only want to work, but seek for adventures. It's a great place to begin your TEFL career.