Don’t use Google Translate. Seriously. Don’t use any of these translation machines. They work with snippets from sentences, translate them word by word and then put them back together to form sentences. The result is often completely incorrect German. Those systems don’t understand flections (changes to words based on gender and cases), and they don’t understand meaning. They will translate “the house” to either “das Haus”, “dem Haus” or “des Hauses”, no matter which one it is actually supposed to be. Those translation machines also don’t recognize homonyms (same word, different meaning) or special context.
How about real books, paper dictionaries? They are not bad but especially when you have studied for a while, they often don’t contain sufficient information.
Here’s what you should use: good online dictionaries. They include all the necessary information, often contain example sentences, and they have an audio function, so you can hear the pronunciation of new words. They most certainly will also give you a long list of possible translations, which can be overwhelming in the beginning, but eventually you will be able to work with it – forums are a good place to ask, and you can also look for example sentences.
Here are my favourites:
Leo provides tons of information, such as if verbs are reflexive, which case the reflexive pronoun takes on, which case follows a preposition, verb-preposition combinations, examples, audio, and a discussion forum. It needs some time getting used to because of the sheer amount of information, but in my opinion it’s the best out there.
Very simple and crisp layout, the fastest when looking for a translation of a singular word without any Schnickschnack, audio included. Not great for special features such as optional reflexive use of verbs.
Linguee’s very special and useful feature are the example sentences. You also get some extra information and audio, but the best part really is that the word you’re looking for will be presented individually and in the context of a sentence with the English translation. This dictionary also throws out an additional list of examples from the internet (“external sources”) but they haven’t been confirmed and can originate from a site that was badly translated. However, the examples above that list are very good and prevent you from picking the wrong translation in the end.