If you have the time to devote yourself to intensive learning and have money for enrollment, Goethe-Institut is an excellent program. According to a review by "The Washington Post," Goethe-Institut has 125 worldwide locations and fosters understanding between German culture and the host country. Also check with your local university or community college for German classes. And ultimately, if you are able to travel to a German-speaking country, you will have several options available with many universities. Look for the words "Sprachenzentrum" and "Sprachkurse" on university web pages, or look for an international studies page with helpful information in English.
Even if you don't understand the basics, listen to as much German as possible. Notice the sounds, emphasized words and repeated phrases. Try to spell and take note of words that interest you, and create a journal with notes and vocabulary.
Native English speakers have a hard time learning noun gender, especially in the beginning. Use stick-on notes or 3-by-5 cards to label things in your house. The cards serve as visual aids and help you learn vocabulary swiftly. As you progress in your German course, you will use your memorized noun genders "der", "die" and "das" alongside your vocabulary for many other things such as adjective endings and definite and indefinite articles.
Keep a journal and write down words, definitions and uses. Try to make it a daily habit. Review previous entries often.
Practice makes perfect. Don't expect to understand and read, write, comprehend and speak on your first try. Allow mistakes; in fact, welcome them. Review and practice the grammatical exercises, words and rules that are are the most difficult for you. Try not to allow frustration to set in; you will need to repeat, review and practice the language even when you attain fluency.
Ideally, you should travel to a German-speaking country in order to understand the culture and language to their full extent. So many lessons can be learned from everyday occurrences such as grocery shopping or getting a bite to go (zum Mitnehmen).