Writing an essay in another language is a tricky task, but as with all essays, a detailed plan is the best way to start! Once you have a clear idea of what your essay is about, your 3 or 4 arguments and then what you would like to say in your conclusion then you are good to go!
Using some good essay phrases to link your ideas together will really make a difference to your essays. Whether it be 'Meiner Meinung nach' (in my opinion) or 'Dazu kommt noch' (in addition) or even 'Zum Schluss' (in conclusion,' these phrases will make your essay stand out! Perhaps pick 10 of your favourite and learn them off my heart so that you can use them instantly!
The most important thing to do when you have finished writing your essay is to check your work. 99% of the time you will come across a silly error or mistake when reading back over your essay so this is well worth a glace over before you hand in your essay. Common mistakes are: word order mistakes after 'weil' and 'obwohl,' mistakes with cases e.g. 'mit der Katze,' or simply when umlauts are forgotten about.