It is important to figure out what you want to say before you start writing. Scribble down the main points of your essay/story.  Try to think and write in German, even your draft. Avoid jotting it down in English and then translating it into German. This leads easily to mistakes and sentence structure which sound wrong.
Plan the grammatical forms of your writing like tenses, moods, opinions, hypothetical events.
Please continue reading if you are interested in some major points for your German written work. These tips are especially useful for VCE students who prepare for their written exam. However these points are also valid when speaking the German language.
Think style: Try not to begin each sentence with the subject. Prepositional phrases, adverbs and subordinate clauses work well and help to highlight particular ideas.
Think familiar structures: Write down verbs and structures you already know in German, look up unknown words in a dictionary. Avoid using electronic translation programs, they sound mostly wrong, even with simple phrases. When using your dictionary, check the meaning in English and German to avoid misuse.
Think variety: Using a big variety of verbs and avoiding the overuse of haben, sein und machen will demonstrate your understanding of the German language. Avoid the repeated use of the Present Perfect in your writing, using Simple Past helps avoiding too many haben und sein structures. The Present Perfect is the preferred style of conversational German and informal writing.
Think linking ideas: Conjunctions are the obvious choice when linking your ideas in a chronological and logical way. Don't forget to double check what kind of conjunctions you used, do they change the word order or not? Where does the verb go?
Think correct case: When using articles, personal or possessive pronouns make sure you put them in their correct case. Are they used as the subject, direct/ indirect or possessive object? Do they match in gender and number (singular/plural)?
Think prepositions: Prepositions are important linking elements within a sentence. And yes, they also take different cases, sometimes even Accusative and Dative case. Reread your text and check for the correct use and case of your preposition. When using two-way prepositions ask  the questions Wo?(+ Dative) and Wohin? (+Accusative).
