The best way to learn a new language is through immersion with native speakers. Travel to a German-speaking country such as Germany, Austria or Switzerland, or go to an English-speaking country such as the U.S., Canada, Great Britain or Australia. This will force you to use the words in that pocket dictionary and to hear them used correctly in context.
Find a language partner or tutor if traveling is not an option. People from all over the world, especially from East Asian countries such as Korea and Japan, are rushing to other countries to learn English. Many libraries and community centers offer free English tutoring or conversation partners to immigrants and exchange students from these countries. Offer to tutor or converse with someone in your native language who wants to learn it, in exchange for learning English.
Purchase a language software program you can upload onto your computer, or find a language recording you can listen to during car rides or other free time. Opportunities for speaking and learning German are less common than English, and the dense German grammar can be frustrating for a new learner. However, more software programs today offer features that move beyond simply grammar study. Some language series -- for instance, Rosetta Stone -- teach language through pictures. Such a program helps a learner internalize a complicated grammar system, such as German, rather than memorize it.
Sign up for an English or German language course at a local community college or adult education center. Most schools offer classes in both languages, and larger cities are likely to have language-learning institutes that teach the most useful aspects of German and English in practical situations.