Even though a closer inspection of German reveals that it's not so different from English after all, there are still a few points of confusion and errors to be avoided if you are to make your language sound authentic and gain top marks at native speaker level. It is exceptionally important to remember the key points and to avoid saying something unintentionally in a foreign country. This will save you both confusion and embarrassment.
The number one mistake made when learning every foreign language, whether it's German or otherwise is thinking in your mother tongue. In this way, you will often make mistakes with sentence order, correct prepositions, pronouns and occasionally verb tenses. This is a common error and one that is made by almost every beginner. It is sometimes referred to as a verbatim translation; that is to say a word for word translation and can very often lead to Anglicisms, something to be avoided if you are to enhance your German up to native level. This mistake can be avoided once you get into the German mood and your language will soon become more idiomatic if you ditch the verbatim habit.
Gender is another common mistake because it is a concept not generally known to English speakers. Nouns that are feminine and others that are masculine is a very strange idea to those that have never heard of noun genders before. It is vitally important when learning German that you learn each new word with its article as well. In this way you shouldn't have too much of an issue when it comes to remembering which gender the noun belongs to. On a similar note, always try to remember any unusual verb uses and prepositions that are used with them. In this way you will never get caught out by irregular verbs and noun genders, making your language far more accurate.
For some reason, English has ceased to have two different second person forms and now only has the one – you. This is exceptional and the vast majority of languages have two forms, one usually being the formal and the other informal. German isn't an exception and it is very easy to be deceived by sie and du when in the early stages of learning German. It is important that you make this distinction as the way you address somebody may need to change if you are addressing someone in a more formal way; you can appear disrespectful if you don't get this right.
German is similar to English but that does not mean that you can take your eye off the ball even for a second. You must get all of the finer points correct in order to avoid making silly errors either when speaking or particularly when writing German. Learning some of these rules and revising them every time you need to implement them is a good way to get into the right frame of mind and to put your brain into German mode, if you get this right you will begin to speak the language instinctively.