Learning a new language can be a frustrating thing because you are retraining your mind, your mouth and your paradigms. After studying and applying these techniques the process will become easier.

1- Immerse Yourself: When you are learning another language you are really learning another culture too. Take for instance English there are sayings like 'put it in layman's terms' or even slang like 'you are making bank at your job!' Phrases such as these are formed from a cultural background and not because the actual definition of the sentence makes sense. When you are learning German try to learn as much about the culture as you can so that you too can understand what is being said rather then just the definition of the words. Here is a site with a ton of German Movie titles to select from and another site with a list of German musicians:
Movies in German
German Artists
2- Use Flashcards to Study: When use a list to study our mind is often memorizing the position of the word relative to the other words. With flashcards you are learning the word as it stands alone not because of its ties to the words around it.

3-Practice Out Loud- Most of us are very self conscious when it comes to something we are learning because we don't want to look or sound like an idiot. So the repercussion of this is we practice our vocab in our head. Well by the end of all our quiet practicing we will speak perfect German... in our head. You are going to speak German you have to retrain your mouth to make different shapes and sounds so practice out loud. It would be like practicing football in your head and never setting foot on the field before the big game. Practicing in silence can help some but ultimately its action that will train you.

4- Be Willing to Change your Paradigm: German isn't another way to speak English. It is its own culture, it has its own meanings, and its own rules. Don't try and make you English speaking paradigms fit against the German world because they won't. There won't always be a direct translation from German to English and there won't always be a word in German for every English word. You are learning a new way to express yourself and not a new way to sound when you talk. Remember German offers ways to express yourself that English doesn't and vica versa don't let that scare you or hold you back from enveloping yourself in the German world.

5- Find a Good Course: Everyone's circumstances are different. Some may have the opportunity to enter a classroom for instruction in German. And others may not live close enough to somewhere that offers that kind of service or doesn't have a schedule that allows them to be tied to a class so online works better. Either way whether its in class or online, find one that is recommended and that tailors your learing style. You won't stick with it if you feel that the logistics of the course take more time then the studying. Look up a local college or high school and see if they offer a class or go to Learn How to Speak German for some recommended courses.